Closes gh-20257

Closes gh-20256

Closes gh-20255

Closes gh-20254

Closes gh-20253

Closes gh-20252

Closes gh-20251

Closes gh-20250

Closes gh-20249

Closes gh-20248

Closes gh-20247

See gh-20196

See gh-20198

See gh-20197

This commit makes sure that a fallback embedded datasource is not
created if no suitable connection pool is found and an url has been
explicitly registered.

This is consistent with EmbeddedDataSourceConfiguration as it is using
EmbeddedDatabaseBuilder behind the scenes and the latter does not
honour the configured URL anyway.

Closes gh-19192

Closes gh-20135

Closes gh-19926

* pr/20157:
  Upgrade CI to Docker 19.03.5

Closes gh-20157

See gh-20157

* pr/19202:
  Polish "Verify ssl key alias on server startup"
  Verify ssl key alias on server startup

Closes gh-19202

See gh-19202

See gh-19202

* pr/18915:
  Polish contribution
  Handle JSON keys containing a dot from CF environment as a single path segment

Closes gh-18915

Along with surrounding map keys with dot from VCAP_SERVICES with `[ ]`,
this commit also does that for non-alphanumeric and `-` characters so that
they are not stripped off later.

See gh-18915

See gh-18915

Closes gh-19707

Closes gh-19629

See gh-19926

* pr/19926:
  Polish "Remove unnecessary leading slash in changelog locations"
  Remove unnecessary leading slash in changelog locations

Closes gh-19926

See gh-19926

See gh-19926

Closes gh-20041

* pr/19901:
  Polish contribution
  Handle message of @ResponseStatus-annotated exception with WebFlux

Closes gh-19901

See gh-19901

See gh-19901

This commit upgrades to spring javaformat 0.0.20 and Checkstyle 8.29.

This commit also upgrades to the Checkstyle maven plugin 3.1.0.

See gh-20011

Previously, only the top-level handlers were examined to find the
ContextHandlers and log the context path. If those handlers had
been wrapped, this prevented the ContextHandlers from being found
and an empty string was always logged.

When finding the context path, this commit unwraps the handler held
by a HandlerWrapper until the ContextHandler is found.

Fixes gh-19969