See gh-10515

Closes gh-10632

Closes gh-10631

Closes gh-10630

Closes gh-10629

* gh-10588:
  Polish "Provide informative reason when rejecting request with invalid level"
  Provide informative reason when rejecting request with invalid level

See gh-10588

Previously, bad request with no reason was included in the response.
This commit introduces the reason when invalid log level is sent in the
request.

Fixes gh-10588

See gh-9316

See gh-10587

* gh-10554:
  Honor logging.path config in filePattern for Log4j2 RollingFile

Previously, rolled over files were always written to logs/. This
commit ensures that rotated logs are written into the directory
specified in the application config's logging.path property.

Closes gh-10554

Closes gh-10606

See gh-9316

See gh-9316

See gh-9316

Fixes gh-10608

* pr/10601:
  Fix broken documentation links

Update links following recent project restructure.

Closes gh-10601

* pr/10603:
  Fix broken README.adoc

Closes gh-10603

Update `SpringConfigurationPropertySource` so that it no longer
references types in `org.springframework.boot.env`.

Closes gh-10592

Update the `BinderConversionService` so that it no longer references
classes from `org.springframework.boot.context.properties.bind`.

See gh-10592

See gh-10524

Previously, if Undertow failed to start, some of Undertow's
internal components would have been started but the started field of
UndertowEmbeddedServletContainer remained false. This meant that when
stop() was called nothing was done as the container believed it had
not been started.

This commit updates UndertowEmbeddedServletContainer to stop both the
DeploymentManager and the Undertow instance in start() if an exception
is thrown. This aligns the behaviour of
UndertowEmbeddedServletContainer with that of the Tomcat equivalent.

Closes gh-10528

* pr/10590:
  Change @ConditionalOnClass from Servlet to Flux

Update `ReactiveManagementContextAutoConfiguration` to check for a
`Flux` class rather than `Servlet`.

Closes gh-10590

Update `Binder` so that Maps containing references to themselves may
be bound. The existing stack-overflow protection (required when binding
a bean to a non enumerable source) now only applies to bean properties.

Fixes gh-9801

Update `JavaBeanBinder` so that null instances that are non-instantiable
are not bound.

Fixes gh-10131

Closes gh-9746

* pr/10535:
  Polish MetricsEndpoint
  Support composite registries in MetricsEndpoint

See gh-10535

Update `MetricsEndpoint` to deal with `CompositeMeterRegistry`
instances.

Closes gh-10535