This commit restore the use of the `postProcessRequestHeaders` method
when overridden in a custom HttpExchangeTracer implementation.

Closes gh-13924

* pr/13990:
  Polish "Add global support for JMX unique names"
  Add global support for JMX unique names

This commit ensures that the new "spring.jmx.unique-names" property
deprecates the Endpoint's specific property as they share the same goal.

If both are set with an incompatible value, an exception is thrown
inviting the user to update their configuration.

Closes gh-13990

See gh-13990

This commit adds support for providing a default ThreadPoolTaskExecutor
with sensible defaults. A new TaskExecutorBuilder is provided with
defaults from the `spring.task.*` namespace and can be used to create
custom instances.

If no custom `Executor` bean is present, `@EnableAsync` now uses the
auto-configure application task executor. Same goes for the async support
in Spring MVC.

Closes gh-1563

Closes gh-14000

* pr/13983:
  Upgrade to Kafka 2.0.0

Closes gh-13983

* pr/13988:
  Include @ in javadoc links for annotations

Closes gh-13988

See gh-13988

* pr/13991:
  Return null immediately when sla is null in convertSla()

Closes gh-13991

* pr/13989:
  Update assertion message in AnnotatedClassFinder.scanPackage()

Closes gh-13989

Prior to the changes that fixed #12451,
`FilteredPropertySources` and `CompositePropertySources` were required
by the `PropertySourcesDeducer` to ensure that configuration properties binding
could see changes to the environment even when there was a
PropertySourcesPlaceholderConfigurer in the context. #12451 changed the way
property sources are adapted by `SpringConfigurationPropertySources`, removing the
need for `FilteredPropertySources` and `CompositePropertySources`.

Fixes gh-13738

Fixes gh-13965

* pr/13985:
  Upgrade maven wrapper to Maven 3.5.4

Closes gh-13985

* pr/13982:
  Add dependency management for micrometer-registry-cloudwatch

Closes gh-13982

* pr/13966:
  Polish "Make "MaxSwallowSize" more easily configurable"
  Make "MaxSwallowSize" more easily configurable

Closes gh-13966

See gh-13966

* pr/13973:
  Remove unused dependencies

Closes gh-13973