Refactor extraneous channel events

This change removes JitterBufStats, ChannelReload, and ChannelUpdate
and refactors the following events to travel over Stasis-Core:
* LocalBridge
* DAHDIChannel
* AlarmClear
* SpanAlarmClear
* Alarm
* SpanAlarm
* DNDState
* MCID
* SIPQualifyPeerDone
* SessionTimeout

Review: https://reviewboard.asterisk.org/r/2627/
(closes issue ASTERISK-21476)


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@393284 f38db490-d61c-443f-a65b-d21fe96a405b