ari: Add support for specifying an originator channel when originating.

ari: Add support for specifying an originator channel when originating.

If an originator channel is specified when originating a channel the linked ID
of it will be applied to the newly originated outgoing channel. This allows
an association to be made between the two so it is known that the originator
has dialed the originated channel.

ASTERISK-24552 #close
Reported by: Matt Jordan

Review: https://reviewboard.asterisk.org/r/4243/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@429153 65c4cc65-6c06-0410-ace0-fbb531ad65f3