Closes gh-22737

Previously, waitsForQuietPeriod would iterate 10 times, touching a new
file and then sleeping for 100ms at it did so. With a quiet period of
200ms, this was intended to result in a single change set containing
10 files. However, the test would fail occasionally as multiple change
sets were detected. The test is multi-threaded and is, therefore, at
the mercy of the scheduler. If the thread that is iterating and
touching the files takes over 200ms to be scheduled – exceeding the
watcher's quiet period – the watcher may detect a change set while the
changes are still being made. Eliminating this possibilty would require
the test to participate in the watcher's synchronization, which would
require some changes to its implementation. Instead, this commit
aims to avoid the problem by sleeping for 1/10 of the time (10ms) and
expecting a single change set of 100 files. The hope is that the much
shorter sleep time will result in the file touching thread being
scheduled well within the 200ms quiet period.

Closes gh-22732

Prior to this commit, an entry in the environment map provided to the
build plugin image building goal or task that had a null value would
result in a failure with a message that was difficult to diagnose.

This commit treats env map entries with a null value as an empty
entry to prevent the failure and also make it easier to provide an
explicit empty entry in the Maven XML.

Fixes gh-22703

See gh-21388

Closes gh-22726

Closes gh-22717

Closes gh-22723

Closes gh-22717

Closes gh-22721

* gh-21388:
  Polish "Test the launch script when executed directly"
  Test the launch script when executed directly

Closes gh-21388

See gh-21388

See gh-21388

See gh-22709

Closes gh-22711

Closes gh-22709

Closes gh-22706

Closes gh-22705

* pr/22704:
  Fix broken links to Micrometer registry docs

Closes gh-22704

See gh-22704

Prior to this commit, the livenessState and readinessState health
indicators would not be configured automatically and would be missing
from the "liveness" and "readiness" health groups, leading to 404s when
hitting the `/actuator/health/liveness` or `/actuator/health/readiness`.

This commit ensures that the health indicators beans have the proper
name and revisits the auto-configuration conditions to reflect that as
well.

Fixes gh-22562

* gh-22631:
  Polish "Document properties to enable probe health indicators"
  Document properties to enable probe health indicators

Closes gh-22631

See gh-22631

Document property names to enable probe(readiness/liveness)
health indicators.

See gh-22631

Closes gh-22686

* gh-22681:
  Polish "Look in correct context when finding Liquibase beans"
  Look in correct context when finding Liquibase beans

Closes gh-22681

See gh-22681

See gh-22681

See gh-22645

Closes gh-21570

Closes gh-22094

Fixes gh-21606

Closes gh-22672

Fixes gh-19471

Closes gh-22669