ARI: Implement channel dial.

This creates a new outbound channel, and bridges it to a channel already in
the Stasis application.

(closes issue ASTERISK-21620)

Review: https://reviewboard.asterisk.org/r/2634/


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@393326 f38db490-d61c-443f-a65b-d21fe96a405b
ARI: Implement channel hold/unhold.

This puts the channel on hold (rather than queueing a frame from the channel).

(closes issue ASTERISK-21619)

Review: https://reviewboard.asterisk.org/r/2647/


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@393332 f38db490-d61c-443f-a65b-d21fe96a405b