R1:f33e2de09286

make repo callsigns optional

Summary:
Ref T4245 Make repo callsigns optional
This is far from done and still very ugly. I'm just submitting it to check if i'm solving this in the right places.
Right now there's three places with duplicate code and building the identifierMap in the CommitQuery is very ugly.
If we only want to support this in the user frontend then i could hack it into the Markup rule itself and not touch the CommitQuery. Even uglier but more limited in scope...

Generally this approach…