Added currentBroadcastStartTime
PLAT-1762
Resetting currentBroadcastStartTime
PLAT-1762
Saving lastElapsedRecordingTime after all media servers unregistered
PLAT-1749
Merge branch 'IX-9.19.5-PLAT-1762' into IX-9.19.6-PLAT-1762

Conflicts:
	api_v3/lib/types/entry/KalturaLiveEntry.php
Merge pull request #1808 from kaltura/IX-9.19.6-PLAT-1762

IX-9.19.6-PLAT-1762 - currentBroadcastStartTime