Closes gh-21071

Closes gh-21070

Update `WebMvcAutoConfiguration` to automatically apply cors
configuration to the `WelcomePageHandlerMapping`.

Fixes gh-21048

* gh-21067:
  Polish "Update validation of Micrometer configuration"
  Update validation of Micrometer configuration

Closes gh-21067

See gh-21067

See gh-21067

This commit reviews the current timeout options. It creates a connection
and request sub-namespace to separate concerns a bit more.

Closes gh-19673

Closes gh-21065

Closes gh-21049

* improve-es-config:
  Polish
  Improve Elasticsearch RestClient customization capabilities

Closes gh-20994

This commit harmonizes the change made to @DefaultValue to the
annotation processor. If such annotation is added to a scalar value with
no value at all, no default value is produced.

Closes gh-18917

See gh-20994

At present, RestClientBuilderCustomizer allows general customization of RestClientBuilder.
This is troublesome for users that want to customize `HttpAsyncClientBuilder` and
`RequestConfig.Builder` since those are set on the `RestClientBuilder`. By customizing
those two builders user lose out on Spring Boot's support for binding username, password,
connection-timeout and read-timeout properties from `"spring.elasticsearch.rest"` namespace.

This commit enhances the `RestClientBuilderCustomizer` with support for customizing
`HttpAsyncClientBuilder` and `RequestConfig.Builder` by providing additional `customize`
methods that accept the aforementioned builders. Both new methods are optional as they have
no-op default implementations.

See gh-20994

Closes gh-21062

Closes gh-21061

Closes gh-21053

Closes gh-21052

Update `NettyWebServer` so that the `PortInUseException` is not thrown
for permission denied errors.

Fixes gh-19807

Update classes that throw `PortInUseException` so that they also
include the cause. Prior to this commit the cause was not included
which could make diagnosing the real cause difficult.

See gh-19807

Closes gh-21050

Fixes gh-20745

Fixes gh-21020

Closes gh-21049

When using constructor binding, if no properties are bound to
a nested property, the top-level instance will be created with a
null value for the nested property.
This commit introduces support for an empty `@DefaultValue` which
indicates that an instance of the nested property must be created
even if nothing is bound to it. It honors any `@DefaultValue`
annotations that the nested property might have in its constructor.

Closes gh-18917

Closes gh-21047

Update `ConditionalOnAvailableEndpoint` so that it now uses the same
matching code as the endpoint filter. This allows the condition to
match endpoint IDs that contain a dash.

In order to share logic, the `ExposeExcludePropertyEndpointFilter` class
has been deprecated and its logic moved to a new `expose` package
under `IncludExcludeEndpointFilter`. This filter is used by both the
`OnAvailableEndpointCondition` and the auto-configuration classes.

Fixes gh-21044

Closes gh-21041

Closes gh-21039

Fixes gh-21034

Closes gh-19674

This commit makes sure that our copy of the IsolationLevel enum is
consistent with what Kafka 2.4 provides

Closes gh-20822

* gh-21030:
  Fix links to CLI binaries in non-snapshot builds

Closes gh-21030

See gh-21030

* gh-21033:
  Fix anchors in links to Maven and Gradle plugin docs

Closes gh-21033

See gh-21033

This partially reverts commit 1f8ea54c.

Closes gh-21032

This commit harmonizes how Graphite is configured. If tagsAsPrefix is
set, it is used transparently. Otherwise, the new native tagging system
is used.

See https://github.com/micrometer-metrics/micrometer/pull/2007

Closes gh-20884

Closes gh-21028