HIGH PROFILE label changes

These changes will:

1. Implement HIGH_PROFILE for SSM preferred event.
2. Post a log in gracedb saying which criteria was fulfilled for applying HIGH_PROFILE.

The change for distance criteria will be done in the future MR after a consensus is reached for distance: Skymap HIGH_PROFILE condition modified to include events with mean distance < 2Gpc.

Addressed #836 (closed), userguide#389 (closed), #842, #888 (closed)