add significant/less-significant alert condition in superevent manager
- EM_Selected now indicates completeness, passing less-significant far, launches automated alert pipeline.
- EM_SelectedSignificant indicated completeness and passing confident far for non-EW events.
- EARLY_WARNING on the superevent indicates presence of a confident EW event.
This refactors the changes to superevents.py from !1051 (merged).
Edited by Deep Chatterjee