Add mass monitors to RecoMon

Sits on top of !233 (merged)
Teach RecoMon to produce mass peaks.
Added the usual suspects \pi^0/\eta\to\gamma\gamma, K_S^0, \Lambda, \Xi^-, \Omega^-, D^0\to K^-\pi^+, D^{*+}, D^+\to K^-\pi^+\pi^+, D^+/D_s^+\to\phi\pi^+, \Lambda_c^+/\Xi_c^+\to pK^-\pi^+, J/\psi\to\mu^+\mu^- and e^+e^-.
The first trick (hack) was to not force the persistency to write to the usual locations; as done in https://gitlab.cern.ch/lhcb/Moore/-/blob/master/Hlt/RecoConf/options/run_two_hlt2_recos.py (many thanks to @sstahl for the discussions on this and the pointer to this configuration!).
The rest was figuring out how to setup the control flow (require_pvs needs to be factored out - even when setting a unique name for the VoidFilter).

\cc @decianm