ari: Add Snoop operation for spying/whispering on channels.

The Snoop operation can be invoked on a channel to spy or
whisper on it. It returns a channel that any channel operations
can then be invoked on (such as record to do monitoring).

(closes issue ASTERISK-22780)
Reported by: Matt Jordan

Review: https://reviewboard.asterisk.org/r/3003/
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Merged revisions 403117 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@403118 f38db490-d61c-443f-a65b-d21fe96a405b
ari: Add events for playback and recording.

While there were events defined for playback and recording
these were not actually sent. This change implements the
to_json handlers which produces them.

(closes issue ASTERISK-22710)
Reported by: Jonathan Rose

Review: https://reviewboard.asterisk.org/r/3026/
........

Merged revisions 403119 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@403120 f38db490-d61c-443f-a65b-d21fe96a405b