Move device state distribution to Stasis-core

In the move from Asterisk's event system to Stasis, this makes
distributed device state aggregation always-on, removes unnecessary
task processors where possible, and collapses aggregate and
non-aggregate states into a single cache for ease of retrieval. This
also removes an intermediary step in device state aggregation.

Review: https://reviewboard.asterisk.org/r/2389/
(closes issue ASTERISK-21101)
Patch-by: Kinsey Moore <kmoore@digium.com>


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@385860 f38db490-d61c-443f-a65b-d21fe96a405b
Move presence state distribution to Stasis-core

Convert presence state events to Stasis-core messages and remove
redundant serializers where possible.

Review: https://reviewboard.asterisk.org/r/2410/
(closes issue ASTERISK-21102)
Patch-by: Kinsey Moore <kmoore@digium.com>


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@385862 f38db490-d61c-443f-a65b-d21fe96a405b