Inline typecasting helpers from Column to the appropriate types

Use the generic type map for PostgreSQL OID registrations

Delegate predicate methods to injected type object on Column

Use the generic type map object for mysql field lookups

Distinguish rake assets:clobber from rake assets:clean

[ci skip]

Replace `type_cast` case statement with delegation

Fix confusing exception in ActiveSupport delegation

Have Postgres OID types inherit from general types

Use general types for mysql fields

All subclasses of column were now delegating `type_cast` to their
injected type object. We can remove the overriding methods, and
generalize it on the `Column` class itself. This also enabled us to
remove several column classes completely, as they no longer had any
meaningful behavior of their own.

Delegate type_cast to injected type object in mysql

Using general types where possible. Several more can go away once
infinity gets figured out.

Delegate `#type_cast` to injected type objects on SQLite3

Fixed the inferred table name of a HABTM auxiliar

Fixes #14824.

Use generated binstubs in guides examples. [ci skip]

[ci skip]

While running Sqlite3 memory tests I encountered the following error:

```
Finished in 69.416366s, 58.0267 runs/s, 162.3681 assertions/s.

  1) Error:
ActiveRecord::Migration::ChangeSchemaTest#test_add_column_with_timestamp_type:
NoMethodError: undefined method `type' for nil:NilClass
    /Users/senny/Projects/rails/activerecord/test/cases/migration/change_schema_test.rb:244:in `test_add_column_with_timestamp_type'

4028 runs, 11271 assertions, 0 failures, 1 errors, 1 skips
```

This was because the table `testings` was used in multiple test-cases.
This resulted in a wrongly cached schema on `ActiveRecord::Base.schema_chae`.

/cc @zuhao

Closes #15122
Closes #15107

Un-define :to_json for Customer class after stubbing.

Deregister csv renderer after test to prevent leak.

This reverts commit 5c224de9.

Conflicts:
	actionpack/lib/action_dispatch/journey/visitors.rb

5c224de9 introduced a bug in the
formatter.  This commit includes a regression test.