This PR adds the allocations to the instrumentation for template and
partial rendering.

Before:

```
  Rendering posts/new.html.erb within layouts/application
  Rendered posts/_form.html.erb (9.7ms)
  Rendered posts/new.html.erb within layouts/application (10.9ms)
Completed 200 OK in 902ms (Views: 890.8ms | ActiveRecord: 0.8ms)
```

After:

```
  Rendering posts/new.html.erb within layouts/application
  Rendered posts/_form.html.erb (Duration: 7.1ms | Allocations: 6004)
  Rendered posts/new.html.erb within layouts/application (Duration: 8.3ms | Allocations: 6654)
Completed 200 OK in 858ms (Views: 848.4ms | ActiveRecord: 0.4ms | Allocations: 1539564)
```

Currently, the following error is shows only when run the test using
`bin/test`.

```
./bin/test -w test/template/log_subscriber_test.rb
Run options: --seed 17167

# Running:

/rails/actionview/test/template/log_subscriber_test.rb:34: warning: instance variable @defined_root not initialized
```

In `AVLogSubscriberTest`, if the `Rails.root` is not defined, define the
method and undef it in teardown.
https://github.com/rails/rails/blob/master/actionview/test/template/log_subscriber_test.rb#L21..L33

However, in `bin/test`, `Rails.root` is defined, which results in referring to
uninitialized variables and warnings.

This reverts commit 3420a145, reversing
changes made to afb66a5a.

Implement naive partial caching mechanism.

Add test for LogSubscriber

Use ActionView::Base#log_payload to store log_subscriber's payload, so we can pass cache result into it.

Fixed tests

Remove useless settings

Check if #log_payload exists before calling it. Because other classes also includes CacheHelper but don't have is attribute

Use @log_payload_for_partial_reder instead of #log_payload to carry ActionView's payload.

Update test's hash syntax

Add configuration to enable/disable fragment caching logging

Remove unless test and add new test to ensure cache info won't effect next rendering's log

Move :enable_fragment_cache_logging config from ActionView to ActionPack

Apply new config to tests

Update actionview's changelog

Update configuration guide

Improve actionview's changelog

Refactor PartialRenderer#render and log tests

Mute subscriber's log instead of disabling instrumentation.

Fix typo, remove useless comment and use new hash syntax

Improve actionpack's log_subscriber test

Fix rebase mistake

Apply new config to all caching intstrument actions

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

Added log "Rendering ...", when starting to render a template, to log that we have started to render something, at the very beginning.
This helps to easily identify queries from controller vs views

Fixes #23710

Augments the collection caching with some instrumentation that's logged.

For collections that have been cached like:

```ruby
<%= render partial: 'notifications/notification', collection: @notifications, cached: true %>
```

We'll output a line showing how many cache hits we had when rendering it:

```
  Rendered collection of notifications/_notification.html.erb [0 / 100 cache hits] (3396.5ms)
```

We can use another way to instantiate ActionView::Base, by passing
renderer as a first option. Thanks to that we can just pass prefixes to
LookupContext instead stubbing them on the controller. This is also good,
because that kind of API is used in Rails code.

For example, calling hello.erb is now deprecated. Since Rails 3.0
passing the handler had no effect whatsover. This commit simply
deprecates such cases so we can clean up the code in later releases.

Move Rails::LogSubscriber to ActiveSupport::LogSubscriber, allowing frameworks like ActiveRecord and ActiveResource to log outsude Rails::Application [#4816 state:resolved]

This reverts commit eec2d301.

This commit broke tests. You cannot have a file called "bundler" on the load path.

In heterogeneous collections, neither the @path nor the @template are available, so we need to tell that we are simply rendering a collection.