Co-Authored-By: NAdrien Lecharpentier <adrien.lecharpentier@gmail.com>

- Uses eslint for JS and stylelint for LESS
- Uses default configs
- Default severity set to warn to avoid breaking current builds

- Jest was chosen because it's the most feature-complete one
- Fixes tests so that they would work with the new JS modules
- Removed the gulpfile unused test dependencies
- Enabled tests in maven

- It was previously done using cli, which could fail on windows
- Added plugin to clean up webpack build folder
- Cleaup on the package.json

- moves the fonts back to the war/src/main/webapp/css folder

[JENKINS-60634] Define $WORKSPACE_TMP for (non-Pipeline) builds

Fix typos & spelling in Javadoc and WebUI

[JENKINS-40228] Remove Enable Security checkbox in the Global Security configuration (follow-up)

[JENKINS-60641, JENKINS-60644] incorrectly converted AntClassLoader.loadResource to a Java 5 for-loop

Without fix, Jenkins startup fails:
java.lang.NullPointerException
	at java.io.Reader.<init>(Reader.java:78)
	at java.io.InputStreamReader.<init>(InputStreamReader.java:113)
	at org.apache.commons.io.IOUtils.copy(IOUtils.java:2440)
	at org.apache.commons.io.IOUtils.toString(IOUtils.java:1084)
	at io.jenkins.plugins.loads_resource.Main.stuff(Main.java:36)

[JENKINS-60449] Prevent endless recursion in SezpozModule.resolve