New 'manager show settings' CLI command.

See the CHANGES file for more details.

(closes issue #16343)
Reported by: pabelanger
Patches:
      issue16343.patch.v5 uploaded by pabelanger (license 224)
Tested by: pabelanger, tilghman, lmadsen

Review: https://reviewboard.asterisk.org/r/630/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@261180 65c4cc65-6c06-0410-ace0-fbb531ad65f3