JENKINS-21037
JENKINS-21037: reformatted, refactored instance check
JENKINS-21035: implementation last job configuration modification
Merge branch 'JENKINS-21037' of
https://github.com/krulls/extra-columns-plugin

Conflicts:
	src/main/resources/jenkins/plugins/extracolumns/Messages.properties
	src/main/resources/jenkins/plugins/extracolumns/Messages_de.properties
Added <?jelly escape-by-default='true'?>
Added config.jelly files
Small refactoring and fixed line breaking