Docker images and other automation use cases often want to make Jenkins
use specific port. Today they do this via init.groovy.d with a
problematic sleep timeout, so allow them to control this value via
system property.

[FIX JENKINS-11016] Add button that allows retrying core update

[FIXED JENKINS-31219] A CloudProvisioningListener can prevent provisi…

[FIXED JENKINS-31954] Stack overflow reconfiguring some settings where Descriptor.newInstance is gratuitously overridden.

Ensure that no warnings appear during startup

Deprecating subclassing of Plugin

[JENKINS-31395] Footer does not work fine in some situations

[JENKINS-31776] CLI command online-node extracted from core to CLI

JENKINS-29059: Display cron run times after warnings if warnings occur.

[JENKINS-30914] Add extra logging to the queue

Routine errors listening for UDP broadcast or DNS multicast should not print stack traces to the log.