The test system I set up to verify resolution of customer(s)' issues driving this change, required
additional changes in order to fully resolve the issues at hand. As a result I am bundling these
changes:

- Moves nodes to being store in separate config files outside of the main config file (improves performance) [FIXED JENKINS-27562]
- Makes the Jenkins is loading screen not block on the extensions loading lock [FIXED JENKINS-27563]
- Removes race condition rendering the list of executors [FIXED JENKINS-27564] [FIXED JENKINS-15355]
- Tidy up the locks that were causing deadlocks with the once retention strategy in durable tasks [FIXED JENKINS-27476]
- Remove any requirement from Jenkins Core to lock on the Queue when rendering the Jenkins UI [FIXED-JENKINS-27566]

(cherry picked from commit cf2b02dc)

Conflicts:
	changelog.html

(cherry picked from commit 87ab95e7)

My plan is to remove this in a while.

Although the plugiun manager was vulnerable getting information
out of Jenkins was harder - however it would still be possible to
do bad things such as reading from /dev/zero on Linux

Allowing correlation/tracking all the way through the lifecycle

Review comments fixed:
 Added license header
 Reformat the issue comment
 Restricted NoExternalUse
 toLowerCase in English locale
 lesser resolution of declared exception from the test

Addresses some comments received after the original fix was merged.

Reproducible for example via HelpLinkTest.testMatrixConfig.
Otherwise have: matrix-project → script-security → matrix-auth → windows-slaves → antisamy-markup-formatter → matrix-project
Tried to come up with a generic way of doing this automatically, but failed.
Just because we bundle a particular build of some plugin does not mean it was built against anything recent,
and for use on older cores it may well need some of those implicit dependencies.

(cherry picked from commit 0bd831e2)

(cherry picked from commit 747d550c)

(cherry picked from commit 071951e6)

(cherry picked from commit 04aace98)

(cherry picked from commit e4ba41d5)

(cherry picked from commit 5d9e4d7b)

(cherry picked from commit b9d8f554)

(cherry picked from commit 42195d83)

(cherry picked from commit dbed3044)

Conflicts:
	core/src/main/java/hudson/model/Run.java

(cherry picked from commit d72fda46)