Closes gh-15274

Closes gh-15211

This commit adds `ElasticsearchRestHealthIndicator`, a new
`HealthIndicator` for Elasticsearch, using the Elasticsearch "low level
rest client" provided by the
`"org.elasticsearch.client:elasticsearch-rest-client"` dependency.

Note that Spring Boot will auto-configure both low and high level REST
clients, but since the high level one is using the former, a single
health indicator will cover both cases.

See gh-15211

See gh-15273

* pr/14985:
  Polish contribution
  Allow to disable SSL client authentication on the management port

Closes gh-14985

When server and management are at different ports, and when server
requires TLS client authentication, then there is no simple method to
disable TLS client authentication for management port.

This commit adds an additional "none" option to ssl.client-auth.

Example:

    server.port=8080
    server.ssl.enabled=true
    server.ssl.client-auth=need
    management.server.port=8081
    management.server.ssl.enabled=true
    management.server.ssl.client-auth=none

See gh-14985

Closes gh-15317

Closes gh-15227

See gh-15315

* pr/15312:
  Replace DirectFieldAccessor usages by hasFieldOrPropertyWithValue

Closes gh-15312

Closes gh-15311

* gh-15295:
  Warn about Quartz dropping tables on restart

Closes gh-15295

* gh-15310:
  Polish "Document that test slices should not be combined"
  Document that test slices should not be combined

Closes gh-15310

See gh-15310

Closes gh-15048

Closes gh-1828

* gh-15143:
  Polish "Trim whitespace when coercing to a LogLevel"
  Trim whitespace when coercing to a LogLevel

Closes gh-15143

See gh-15143

Closes gh-15192

This commit makes the repackager more lenient when it is invoked several
times in the same lifecycle.

Closes gh-15034

Closes gh-15294

Closes gh-15191

Closes gh-15167