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)

* [JENKINS-31417] CLI command connect-node extracted from core to CLI

connect-node extended to accept multiple node names
connect-node covered by test-cases

* Slighty modified Javadoc

* Fixed translations after rebase

* [JENKINS-34531] Extended CLI online-node for accepting multiple agents

Polished and extended related TC as well.

* Simplified string composition

* Simplified initialization of HashSet

[FIXED JENKINS-34880] do not show warnings if tool installer is present in at least 1 update site (#2361)

* [JENKINS-34854] - Migrate missing Integer and Boolean properties to SystemProperties

* [JENKINS-34854] - API methods for Long variables

* [JENKINS-34854] - Migrate Long settings to SystemProperties

* [JENKINS-34854] - Leftover change (I should use Save All)

* [JENKINS-34854] - Some fixes in Long methods Javadoc and log messages

* [JENKINS-34244] Some UX improvements in the New item form
* [JENKINS-34244] Submit button has three-state behavior
* [JENKINS-34244] New helper methods were added to make easier the form validation. Focus behavior reviewed

* Handle legacy use of iconSize as a variable

When iconSize was set as a jelly variable, not passed as an attribute,
the value was not being normalized to an IconSizeClass. Fixes
JENKINS-25220.

* Evaluate attrs.iconSize explicitly.

[JENKINS-33663] - Upgrade wizard

Add Upgrade Wizard
Add 'replace' handlebars method in jenkins.js
Fix state transitions to follow a single basic pattern
Suggested plugins selected by default
Add an install state for INITIAL_SECURITY_SETUP
Removed duplicate setupWizard.js on page [FIX JENKINS-34676]
Exclude plugins which are already installed when determining platform
Change 'snooze' to not look like a 'close' button
Make sure unlock screen doesn't show up after new install
Add compatibility check when offering suggested plugins
More appropriate handling of security token filter

[JENKINS-34858] - Listed Parameters should reflect what was used when the build ran

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

- [x] - Avoid String concatenation
- [x] - Switch to R/W lock instead of the specialized container with a significant overhead

Align /about: automation and not just CI server

* Test process cleanup can be suppressed changing BUILD_ID variable

Jenkins is an automation server, not just a CI one.

[FIX JENKINS-34857] Don't throw Exception when Jenkins.getInstance() yields null