Closes gh-18693

* pr/18536:
  Polish "Upgrade to Jetty 9.4.21.v20190926"
  Upgrade to Jetty 9.4.21.v20190926

Closes gh-18536

See gh-18536

See gh-18536

Closes gh-18691

Closes gh-18660

Closes gh-18679

* pr/18673:
  Polish "Apply dependsOn semantic between Liquibase and JPA"
  Apply dependsOn semantic between Liquibase and JPA

Closes gh-18673

See gh-18673

This commits restores the dependency between Liquibase and the JPA
EntityManager even if a custom `SpringLiquibase` is configured.

See gh-18673

This commit removes the override proxyBeanMethods as the aliased
attribute is taking precedence.

Closes gh-18682

* pr/18604:
  Optimize debug level logs

Closes gh-18604

See gh-18604

* pr/18632:
  Polish "Add missing package-info files"
  Add missing package-info files

Closes gh-18632

See gh-18632

See gh-18632

* pr/18637:
  Narrow type for Tomcat 'locale' and 'encoding' properties

Closes gh-18637

See gh-18637

* pr/18675:
  Polish "Restore proxying of @Bean methods in @TestConfiguration"
  Restore proxying of @Bean methods in @TestConfiguration

Closes gh-18675

See gh-18675

See gh-18675

Closes gh-18669

* pr/18665:
  Polish

Closes gh-18665

See gh-18665

Closes gh-18650

* gh-18648:
  Test the Gradle Plugin against Gradle 5.6.3

Closes gh-18648

See gh-18648

Now that we're in the RC phase and close to release, we only want to
pick up maintenance releases of our managed dependencies. This commit
updates bomr's config accordingly.

Closes gh-18626

Closes gh-18525

Previously, the documentation did not describe how to combine
multiple security components when one component's
WebSecurityConfigurerAdapter or SecurityWebFilterChain would cause
the other components' beans of the same type to back off.

This commit adds a note that such cases should be handled by the user
defining their own WebSecurityConfigurerAdapter or
SecurityWebFilterChain that configures the use of all of the
components as required.

Closes gh-18507

This commit renames the `server.jetty.idle-timeout` property to
`server.jetty.thread-idle-timeout`, since there are other timeout
properties that are not tied to the threadpool configuration (e.g. the
connection idle timeout).

We might regroup thread-related properties in a dedicated group in the
future, see gh-18620.

Fixes gh-18615

* gh-18619:
  Remove accidental JavaVersion.current() call in BootRun

Closes gh-18619

It was added accidentally in d2b28ceb.

See gh-18619

Previously, the methods were named addServerProcessors and
setServerProcessors which wasn't aligned with them taking
socket factory processors (ServerRSocketFactoryProcessor) as an
argument.

This commit renames the methods to align them more closely with the
type of their arguments.

Closes gh-18617