Create external sky maps for offline targeted subgrb uploads; fixes #312
We are tasked with creating external sky maps not only for 'online' GCN GRBs, but also for 'offline' uploads from our MOU partners with regards to the joint targeted searches.
The design is to create an external sky map immediately after the external event is created in GraceDB, triggered by the resulting 'new' LVAlert message, rather than in handle_grb_gcn
as is done with events from GCN.
This change results in the creation of an external sky map before the RAVEN search occurs, meaning we will be able to calculate the joint FAR with sky map information from the start.
Edited by Brandon Piotrzkowski