Minor JS cleanup

- Make more functions use the CN namespace instead of the global scope
- Move some JS from the general admin ui file into the banner editor

Change-Id: Ibbbaca38d49a00393534155dc14364132c3ec0fe
Adding License/Credits for CentralNotice

Credits file generated by running:
git log --format='%aN' | sort -u

Change-Id: I467fb604874c4bcce804c30e256d86973243e442
Merge changes I467fb604,Ibbbaca38

* changes:
  Adding License/Credits for CentralNotice
  Minor JS cleanup