[FIXED JENKINS-33780] Introduce listener for slave creation/update/deletion

[FIXED JENKINS-31915] Proxy settings in plugins page are ignored

[JENKINS-35206] - Make the InstallState object deserialization robust against corrupted files (#2387)

* [JENKINS-35206] - Add unit tests for the deserialization logic

* [JENKINS-35206] - Install state should be robust against messed statuses when deserializing objects

* [JENKINS-35206] - Fix the license header in thre test file

See https://github.com/jenkinsci/windows-slave-installer-module/pull/3

* [FIXED JENKINS-34881] - handle non-default security settings for new installs

* Ensure permissions

* Initial security authentication token should still follow redirects

* Lithuanian translation update

* Lithuanian translation update

Optimize PNG images losslessly using zopflipng

* [JENKINS-35178] Fix close button in Safari

* [JENKINS-35178] Removed units

* [JENKINS-35178] Back to the original button design

* State label name as well in order to disambiguate when used from FormValidation#aggregate

* JENKINS-35198 Add failing test for clear identification of the issue and future regression test

* JENKINS-35198 Fix DelegatingComputerLauncher logic for filtering out subclasses as possible delegates

this logic is by default, and subclasses can still allow the selection of other DelegatingComputerLauncher instances as delegates.

Updated Polish translations

Fixes Jenkins build error

contains fixes for GROOVY-7761 and GROOVY-7826

[FIXES JENKINS-34751]

* [JENKINS-35020] Fixed some JSHint errors

* [JENKINS-35020] @kzantow's comment was addressed

* [JENKINS-35020] @kzantow's comment was addressed

[FIXED JENKINS-34883] the legacy default update site can be different from the one specified by ID_DEFAULT

* JENKINS-34708 - UpdateCenter.EnableJob not properly setting status

* Restore if (status instanceof Pending)