Fixes gh-12470

Closes gh-23779

Closes gh-23924

Closes gh-23923

See gh-21454

Closes gh-23922

Closes gh-23789

See gh-23782

Update `ConfigTreePropertySource` with an option to automatically trim
trailing new-line characters.

Closes gh-23826

Update `OriginTrackedPropertiesLoader` with stricter logic around the
document separator. If the preceding or following lines are comments
then the separator will be ignored.

Closes gh-22963

Stop adapting `RandomPropertySource` to `ConfigurationPropertySource`
since it's not useful as a binding source.

Closes gh-21659

* pr/23146:
  Polish 'Support nested @PropertyMapping annotations'
  Support nested @PropertyMapping annotations

Closes gh-23146

See gh-23146

Update `AnnotationsPropertySource` so that nested annotations are
supported. Prior to this commit, annotations annotated with
`@PropertyMapping` that contained nested annotation attributes would
result in instances of `TypeMappedAnnotation` being used as properties.
This usually led to errors due to not being able to convert those to
Strings. This commit makes it so that nested annotations are recursively
mapped to properties. This should allow for more complex configuration
to be mapped from annotations.

See gh-23146

Exclude `@ConfigurationProperties` beans from method validation so
that `@Validated` can be used on final classes without the method
validation post-processor throwing an exception.

This commit introduces a `FilteredMethodValidationPostProcessor` class
which will use `MethodValidationExcludeFilters` to exclude beans from
method validation processing. Using `@EnableConfigurationProperties`
will automatically register an appropriate filter.

Closes gh-21454

Update `ConfigTreeConfigDataResource` so that a wildcard suffix can
be used to import multiple folders. The pattern logic from
`StandardConfigDataLocationResolver` has been extracted into a new
`LocationResourceLoader` class so that it can be reused.

Closes gh-22958

Closes gh-23774

Previously, the test would make an HTTP request and, as soon as the
response was received, it would check the presence and value of the
http.server.requests meter. This create a race condition between the
meter being registered once the response had been flushed and the
meter's presence being checked. If the check won the race, the test
would fail.

This commit updates the test to wait for up to 5 seconds for the
meter to be present and have a count of 1, matching the single request
that has been made.

Fixes gh-23919

Closes gh-23526

Closes gh-23773

Closes gh-23772

Closes gh-23912

Closes gh-23158

Previously, the locale context resolver used with WebFlux could only be
configured by provided a custom LocaleContextResolver bean. By
constrast, when using Spring MVC, the spring.mvc.locale and
spring.mvc.locale-resolver properties could be used to configure the
locale and the resolver (fixed or Accept header) respectively.

This commit introduces spring.web.locale and spring.web.locale-resolver
properties and deprecates their spring.mvc equivalents. The new
properties can be used to configure locale resolution with either
Spring MVC or WebFlux.

Closes gh-23449

Add a dedicate condition annotation to detect when Spring Security is
available but has not been configured by the user. The new annotation
helps simplify quite a few of our auto-configuration classes.

See gh-23421

Replace `WebSecurityConfigurer` and `WebSecurityConfigurerAdapter`
configurations with `WebSecurityCustomizer` or `SecurityFilterChain`
beans.

Closes gh-23421

Update `ConfigurationProperty` with a sensible `toString()` to help
debug task failures.

Closes gh-23771