Reflector rework (for head blob announce)
Created by: kaykurokawa
When running lbrynet as a reflector cluster, it previously did not use the stream info manager at all when receiving streams from clients. Thus a reflector cluster had no knowledge of streams and would not be able to use head blob announce.
This adds stream info manager to the reflector server, and uses this to mark blobs as "should_announce" or not. test_reflectory.py has been modified to check if the stream info is handled properly and blobs are marked as "should_announce" if appropriate.