Bring back missing online rates
This merge request is a minimal version of changes needed to:
- configure the online monitoring outside of the TCK.
- bring back the rates that are missing since the update of the routing bits.
To allow configuration of the monitoring from MooreOnline, HltGlobalMonitor had to be updated to handle the regexes itself, so no knowledge of existing HLT lines is need at the time of configuration.
A new algorithm and a new base class were added to produce the rate plots.
I'd like to deploy this in the pit, to get our plots back ASAP. The merge request is mostly for review and documentation, and can stay WIP and be closed once the more extensive request is merged.
In the full merge request, the base class will live in HltDAQ and HltRoutingBitsWriter also inherits from it.