Add 'sip qualify peer <peer>' command (with AMI SIPqualifypeer)

(closes issue #12524)
 Reported by: ctooley
 Patches: 
       sip_qualify_peer.diff.2 uploaded by ctooley (license 136)
       some modifications for trunk by Corydon76
 Tested by: Corydon76


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@114683 65c4cc65-6c06-0410-ace0-fbb531ad65f3