Add a CLI command to log out a manager user

(closes issue #13877)
Reported by: eliel
Patches:
      cli_manager_logout.patch.txt uploaded by eliel (license 64)
Tested by: eliel, putnopvut



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@173028 65c4cc65-6c06-0410-ace0-fbb531ad65f3