WIP: NVCC compatible monitoring using Gaudi Accumulators

Starting from the work done in !641 (closed), this MR adds Gaudi accumulator histograms and counters for monitoring. This MR moves the monitoring into .cpp files because NVCC is incompatible with Gaudi accumulators. It also has updates for compatibility with the recent changes to the HostBuffers. Work is ongoing to test with the new calo decoding.

In the future some of the histograms will be turned into Monet trend plots and resolve some of the issues raised on !641 (closed) (for example !641 (comment 5639496)).