Further fixes for online dqm monitoring.

This improves the performance, a lot.

(cherry picked from commit 96c8696ed8dba1f31c441a722e4b91b5d070a0b0)
Even more fixes for the monitoring.

(cherry picked from commit 9d781d4340ac0b42378dcbff71d35eee6074fe54)

Conflicts:
	DQMServices/StreamerIO/plugins/DQMProtobufReader.cc
	DQMServices/StreamerIO/plugins/DQMStreamerReader.h
Merge pull request #6108 from dmitrijus/forward73x_5751

Forward port of #5751 to 7_3_X