AthenaMonitoringKernel: Update doxygen documentation
Major cleanup/extension of doxygen documentation and examples:
- Added a
MonAPI
group page (shows up under Modules) that summarizes the user-relevant API - Add unit test and examples for filling with weights
- Change some variable names in the interface (e.g.
converterToDouble
->accessor
)
There are no functional code changes in this MR. cc @tbold @ponyisi @cburton