[FIXED JENKINS-20106] Show different "up" link for jobs in folders

This change determines in the current items parent is the Jenkins
instance. If so, behavior is as before. Otherwise, link to parent
and use the label 'Up' instead of 'Back to Dashboard' similar to
Folders Plugin.
Merge branch 'JENKINS-20106' of github.com:daniel-beck/jenkins into daniel-beck-JENKINS-20106
[JENKINS-20106] Noting.