Add custom prefix to ActiveRecord::Store accessors

The multiple assignments was caused by 37a1dfad due to lost the `to_s`
normalization for given names.

Fixes #32323.

Add a prefix option to ActiveRecord::Store.store_accessor and
ActiveRecord::Store.store. This option allows stores to have identical keys
with different accessors.

Fix Cache `read_multi` with local_cache bug, should returns raw value, not `ActiveSupport::Cache::Entry` instance.

Use ASCII-8BIT paths in ActionDispatch::Static

Ruby 2.6 will not require monkey patched `URI#unescape`

since revision 62897 https://github.com/ruby/ruby/commit/234a30459cdae6aa7da6e28a1082d9c11f315696

The rack gem returns PATH_INFO as an ASCII-8BIT encoded string but it
was being converted to US-ASCII by the match? method because it was
calling Rack::Utils.escape_path. To prevent incompatibile encoding
warnings use ASCII-8BIT strings for the root path and let Ruby handle
any filename encoding conversion.

Fixes #32294, Closes #32314.

[ci skip] Update Action Mailer Documentation

Somehow `test_config_another_database` didn't fail on CI, but it will
fail locally.

https://travis-ci.org/rails/rails/jobs/356212950#L2474-L2482

```
% bundle exec ruby -w -Itest test/generators/app_generator_test.rb -n test_config_another_database
Run options: -n test_config_another_database --seed 7260

# Running:

F

Failure:
AppGeneratorTest#test_config_another_database [test/generators/app_generator_test.rb:417]:
Expected /^\s*gem\s+["']mysql2["'], '~> 0.4.4'$*/ to match "source 'https://rubygems.org'\ngit_source(:github) { |repo| \"https://github.com/\#{repo}.git\" }\n\nruby '2.5.0'\n\n# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'\ngem 'rails', '~> 6.0.0.alpha'\n# Use mysql as the database for Active Record\ngem 'mysql2', '>= 0.4.4', '< 0.6.0'\n# Use Puma as the app server\ngem 'puma', '~> 3.11'\n# Use SCSS for stylesheets\ngem 'sass-rails', '~> 5.0'\n# Use Uglifier as compressor for JavaScript assets\ngem 'uglifier', '>= 1.3.0'\n# See https://github.com/rails/execjs#readme for more supported runtimes\n# gem 'mini_racer', platforms: :ruby\n\n# Use CoffeeScript for .coffee assets and views\ngem 'coffee-rails', '~> 4.2'\n# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks\ngem 'turbolinks', '~> 5'\n# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder\ngem 'jbuilder', '~> 2.5'\n# Use Redis adapter to run Action Cable in production\n# gem 'redis', '~> 4.0'\n# Use ActiveModel has_secure_password\n# gem 'bcrypt', '~> 3.1.7'\n\n# Use ActiveStorage variant\n# gem 'mini_magick', '~> 4.8'\n\n# Use Capistrano for deployment\n# gem 'capistrano-rails', group: :development\n\n# Reduces boot times through caching; required in config/boot.rb\ngem 'bootsnap', '>= 1.1.0', require: false\n\ngroup :development, :test do\n  # Call 'byebug' anywhere in the code to stop execution and get a debugger console\n  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]\nend\n\ngroup :development do\n  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.\n  gem 'web-console', '>= 3.3.0'\n  gem 'listen', '>= 3.0.5', '< 3.2'\n  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring\n  gem 'spring'\n  gem 'spring-watcher-listen', '~> 2.0.0'\nend\n\ngroup :test do\n  # Adds support for Capybara system testing and selenium driver\n  gem 'capybara', '>= 2.15', '< 4.0'\n  gem 'selenium-webdriver'\n  # Easy installation and use of chromedriver to run system tests with Chrome\n  gem 'chromedriver-helper'\nend\n\n# Windows does not include zoneinfo files, so bundle the tzinfo-data gem\ngem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]\n".

bin/rails test test/generators/app_generator_test.rb:411

Finished in 0.174681s, 5.7247 runs/s, 34.3483 assertions/s.
1 runs, 6 assertions, 1 failures, 0 errors, 0 skips
```

It makes to ease to detect a future regression as long as the methods
are covered by this test.

Use PredicateBuilder for bind params in Relation::Batches

Add cancellation info to before filter docs

[ci skip]

Support mysql2 0.4.x and 0.5.x

See flavorjones/loofah#144

Fix system tests transactions not closed between examples

The urls helpers module returned by Rails.application.routes.url_helpers
isn't cached so to prevent the cost of building the module cache it locally.

It should returns raw value, not instance of `ActiveSupport::Cache::Entry`.

Memoize the result of gsubbing @virtual_path

This gets called many times for each virtual_path, creating a new string
each time that `translate` is called. We can memoize this so that it
only happens once per virtual_path instead.

Interpolate '' instead of nil when multiple is false.

"my string #{nil}" results in an additional '' string allocation, I'm
guessing because the nil has to be converted to a string.

"my string #{'[]' if multiple}" results in "my string #{nil}" if
multiple is false. Doing "my string #{''}" does not result in an extra
string allocation. I moved the if multiple logic into a method so I only
had to make the change once.

```ruby
begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update
                your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"

  gem "benchmark-ips"
  gem "rails"
end

def allocate_count
  GC.disable
  before = ObjectSpace.count_objects
  yield
  after = ObjectSpace.count_objects
  after.each { |k,v| after[k] = v - before[k] }
  after[:T_HASH] -= 1 # probe effect - we created the before hash.
  GC.enable
  result = after.reject { |k,v| v == 0 }
  GC.start
  result
end

@html_options = {}

def master_version(multiple=nil)
  "hi#{"[]" if multiple}"
end

def fast_version(multiple=nil)
  str = multiple ? "[]" : ''
  "hi#{str}"
end

def test
  puts "master_version"
  puts allocate_count { 1000.times { master_version } }
  puts "master_version with arg"
  puts allocate_count { 1000.times { master_version(' there') } }
  puts "fast_version"
  puts allocate_count { 1000.times { fast_version } }
  puts "fast_version with arg"
  puts allocate_count { 1000.times { fast_version(' there') } }

  Benchmark.ips do |x|
    x.report("master_version") { master_version }
    x.report("master_version with arg") { master_version(' there') }
    x.report("fast_version")     { fast_version }
    x.report("fast_version with arg")     { fast_version(' there') }
    x.compare!
  end
end

test
```

results:
```ruby
master_version
{:FREE=>-1981, :T_STRING=>2052}
master_version with arg
{:FREE=>-1001, :T_STRING=>1000}
fast_version
{:FREE=>-1001, :T_STRING=>1000}
fast_version with arg
{:FREE=>-1001, :T_STRING=>1000}
Warming up --------------------------------------
      master_version   138.851k i/100ms
master_version with arg
                       164.029k i/100ms
        fast_version   165.737k i/100ms
fast_version with arg
                       167.016k i/100ms
Calculating -------------------------------------
      master_version      2.464M (±14.7%) i/s -     11.941M in   5.023307s
master_version with arg
                          3.754M (± 8.5%) i/s -     18.699M in   5.021354s
        fast_version      3.449M (±11.7%) i/s -     17.071M in   5.033312s
fast_version with arg
                          3.636M (± 6.9%) i/s -     18.205M in   5.034792s

Comparison:
master_version with arg:  3753896.1 i/s
fast_version with arg:  3636094.5 i/s - same-ish: difference falls within error
        fast_version:  3448766.2 i/s - same-ish: difference falls within error
      master_version:  2463857.3 i/s - 1.52x  slower
```

Fix digesting templates with mixed formats

ActiveJob: Remove support for Qu gem.

Reasons are that the Qu gem wasn't compatible since Rails 5.1,
gem development was stopped in 2014 and maintainers have
confirmed its demise. See issue #32273

If an explicit AWS key pair and/or region is not provided in
config/storage.yml, attempt to use environment variables, shared
credentials, or IAM role credentials. Order of precedence is
determined by the AWS SDK[1].

[1]: https://docs.aws.amazon.com/sdk-for-ruby/v3/developer-guide/setup-config.html

Add MySQL JSON reference to ActiveRecord::Store documentation

Move CSP info from 5.2 release notes to guide [ci skip]

Fix failing `QuotingTest#test_quoted_time_utc`

This test fails in specific time.
Example:

If run this test on the machine with time 01:00 am UTC+2,
this test will fail.
Changing representing of 2000-01-01 01:00 am UTC+2 to UTC+0 change
the day, month and even year in our case,
so substitution `"2000-01-01 "` to `""` isn't possible.

```
Failure:
ActiveRecord::ConnectionAdapters::QuotingTest#test_quoted_time_utc
Expected: "1999-12-31 23:01:27"
  Actual: "23:01:27"
```

Related to 7c479cbf

- Add mention about "nonce".

Related to https://github.com/rails/rails/pull/32222#issuecomment-372268157