Update the lquibase test to use `http://` rather than `https://` so that
it can be resolved from the local jar.

Prior to this commit, the published Maven POMs would not pass the Maven
Central mandatory checks.

This commit adds the missing project name and description metadata for
most artifacts. The Spring Boot Gradle plugin artifact was also missing
this information and this is now added in the plugin metadata itself.
This is also updating the project page URL which is now hosted directly
on spring.io.

Fixes gh-21457

Fixes gh-21451

Closes gh-21450

See gh-21350

There's a bug in Undertow that means it may leak a file handle is
the server is stopped immediately after a response to an SSL request
has been received. The stop processing races with Undertow's SSL
support tidying things up after sending the response. When the stop
processing wins, the tidying up fails with a NullPointerException that
prevents an input stream from being closed. On Windows, the input
stream remaining open prevents JUnit from being able to clean up its
temporary directory.

This commit uses Awaitility to wait for the file that's being served
over SSL to be deleted before stopping the server. On Windows, this
will delay the stop processing from beginning until after the tidy up
that's performed after sending the response has been completed,
hopefully eliminating the race condition that resulted in the input
stream being left open.

Fixes gh-21172

Closes gh-17274

Closes gh-21445

* gh-17274:
  Polish 'Add @WebServiceClientTest slice test support'
  Add @WebServiceClientTest slice test support

Closes gh-17274

See gh-17274

Add `@WebServiceClientTest` and related test auto-configuration to allow
slice testing of Spring Web Service client applications.

See gh-17274

Closes gh-21448

Closes gh-21447

Closes gh-21446

Closes gh-21385

Closes gh-21386

Closes gh-21444

Update `EndpointDiscoverer` so that `@Endpoint` and `@EndpointExtension`
beans are created as late as possible.

Prior to this commit, endpoint beans and extension beans would be
created during the discovery phase which could cause early bean
initialization. The problem was especially nasty when using an embedded
servlet container since `ServletEndpointRegistrar` is loaded as the
container is initialized. This would trigger discovery and load all
endpoint beans, including the health endpoint, and all health indicator
beans.

Fixes gh-20714

Closes gh-21353

This reverts commit 7b790299.

See gh-21375

Closes gh-21387

Restore the `getUseRelativeRedirects` method with a `Boolean` object
result and introduce `isUseRelativeRedirects` for the primitive boolean
variant.

See gh-20796

Closes gh-21419

Closes gh-21221

Closes gh-20517

* pr/21378:
  Upgrade to Testcontainers 1.14.1

Closes gh-21378

See gh-21378

Gradle's metadata for a platform does not provide a way to define
exclusions in the same way that can be done in <dependencyManagement>
in a Mavne bom. This means that Gradle 6 users lose the exclusions
that are defined in the pom as Gradle 6 will use the metadata rather
than the pom.

Until such a time as Gradle's metadata supports the configuration of
such exclusions we can avoid the problem by disabling the metadata's
publication.

Fixes gh-21350

See gh-21437

This commit expands the migration check to all deprecated properties,
not only the ones that have been effectively removed. This provides more
information upfront, including keys that still work in the current
release but will need to be renamed sooner than later anyway.

Closes gh-21425