These starters bring the Spring WebFlux experience to Boot.
By default, the Reactor Netty web server is chosen.

* pr/8204:
  Fix ImportAutoConfigurationImportSelectorTests.determineImportsWhenUsingNonMetaWithClassesShouldBeSame()

Fix ImportAutoConfigurationImportSelectorTests.determineImportsWhenUsingNonMetaWithClassesShouldBeSame()

Closes gh-8204

This commit removes `ServerProperties` and `ManagementServerProperties`
auto-configurations. Those properties objects are now created using
`@EnableConfigurationProperties` only.

Closes gh-8108

The changes required to restore our Couchbase support are too involved
and we should hear from the data couchbase team first.

See gh-8200

This commit makes sure that if a `ConfigurationProperties` annotated bean
already exists in the parent context, a new one is not created in the
child anymore.

This makes sure that a single bean exists in a parent/child hierarchy if
`@EnableConfigurationProperties` is processed in both context on the same
class.

Closes gh-8187

Fix couchbase support until a solution is determined for
https://jira.spring.io/browse/DATACOUCH-279

See gh-8200

Closes gh-8203

* pr/8198:
  Use logical 'and' instead of bitwise 'and'

Closes gh-8198

* pr/8202:
  Polish contribution
  Improve spring-boot-sample-cache UX by using Maven profiles

Closes gh-8202

See gh-8202

Update `PropertiesConfigurationFactory` so that the validator is only
set when it supports the target object.

Fixes gh-8149

* pr/8196:
  Polish pid metadata
  Fix pid properties link in documentation

This commit moves the `spring.pid.*` metadata to the relevant project. It
also updates the doc to refer to the new `ApplicationPidFileWriter`
rather than the one in its deprecatred form.

Closes gh-8196

See gh-8196

* pr/8147:
  Remove HikariCP-java6 dependency management

Dependency management for the `HikariCP-java6` dependency is no longer
needed since Java 6 is no longer supported by Spring Boot.

The HikariDriverConfigurationFailureAnalyzer has been updated with the
current message thrown by HikariCP in this failure scenario.

Closes gh-8147

Previously, TestRestTemplate applied the root URI to URIs by
converting them to a String and then passing the String to the
RestTemplate delegate. Being a String, meant that the URI passed
through RestTemplate's standard URI template expansion processing
using the configured UriTemplateHandler. While this caused the root
URI to be applied, it also had the unwanted side-effect of
encoding the URI for a second time.

This commit updates TestRestTemplate so that, when configured with a
RootUriTemplateHandler, it applies the root URI directly and then
passes a modified URI to the RestTemplate delegate. Being a URI means
that no template expansion is performed and the possible double
encoding is avoided.

Closes gh-8163

Closes gh-8182

See gh-8180

See gh-8179

See gh-8148

* pr/8148:
  Polish

Closes gh-8148

* pr/8161:
  Clear system property in SpringApplicationTests

See gh-8101
Closes gh-8161