Closes gh-19560

* pr/19556:
  Add profiles directly to the application environment for tests

Closes gh-19556

Prior to this commit, active profiles were being added to the Spring Boot
application environment by setting the `spring.profiles.active` property.
This could result in profiles getting parsed differently than other uses of `@ActiveProfiles`.
Setting the profiles directly in the `Environment` prevents this parsing.

See gh-19556

Closes gh-19553

Fixes gh-19552

Prior to this commit, the `ErrorController` would override the original
error response status if the error map cannot be written due to content
negotiation with the HTTP client. In that case, the error handling
infrastructure returns a `406 Not Acceptable` response.

This commit improves the `ErrorController` so that
`HttpMediaTypeNotAcceptableException` instances thrown by that
controller are not returned as is but instead we write the error
response with an empty body and the original HTTP error status.

Fixes gh-19545
See gh-19522

* pr/19536:
  Remove deprecated usage of WebTestClientBuilderCustomizer

Closes gh-19536

See gh-19536

* pr/19521:
  Improve Spring MVC auto-configuration section

Closes gh-19521

See gh-19521

Closes gh-19532

* pr/19523:
  Upgrade CI to Artifactory Resource 0.0.10

Closes gh-19523

See gh-19523

Prior to this commit, there was no distinction between explicitly setting
forward headers strategy to a value of NONE and not setting it at all.
This meant that in a cloud environment, a cloud provider was always checked
to see if it was active and using forward headers and there was no way to
prevent that.

This commit changes the default value of the property to null so that there
is a way to determine if the property was explicitly set to NONE.

Fixes gh-19333

Closes gh-19526

This commit also changes the spring framework version
to use snapshots.

Closes gh-18767

Prior to this commit, the Couchbase auto-configuration would use the
bucket credentials when RBAC is configured. This commit ensures that
RBAC is used in that case.

This commit also adds new configuration properties to customize the
bootstrap ports for Couchbase:

* `spring.couchbase.env.bootstrap.http-direct-port`
* `spring.couchbase.env.bootstrap.http-ssl-port`

Fixes gh-19393

Closes gh-19515

* pr/19510:
  Update some copyrights to 2020

Closes gh-19510

See gh-19510

* pr/19508:
  Add reference to OptaPlanner starter

Closes gh-19508

See gh-19508

* pr/19503:
  Polish "Fix outdated reference in ArtemisConfigurationCustomizer javadoc"
  Fix outdated reference in ArtemisConfigurationCustomizer javadoc

Closes gh-19503

See gh-19503

See gh-19503

Closes gh-19498

* pr/19491:
  Polish doc

Closes gh-19491

See gh-19491

Closes gh-19496

* pr/19492:
  Fix typo in BindHandler#onFinish javadoc

Closes gh-19492

See gh-19492

Closes gh-19194

Closes gh-19479

Closes gh-19478

See gh-19473

Closes gh-19472

Closes gh-19473