[mCBM 2022] set max 100 STS digis/evt to cut monster evts + add trigger for monsters

Comparison of the two event classes after the change:

Trg  4: MakeRecoEvents       [   109.7 ms] TS 0, events 22934, Digis: T0 29857 STS  849632 RICH 74884 MUCH 0 TRD 1478405 TOF 682971 PSD 0
                                                                       1.3/evt    37.0/evt    3.3/evt           64.5/evt   29.8/evt
Trg 16: MakeRecoEvents       [     7.6 ms] TS 0, events   933, Digis: T0  1364 STS  152189 RICH  5154 MUCH 0 TRD   78254 TOF  33664 PSD 0
                                                                       1.5/evt   163.1/evt    5.5/evt           83.9/evt   36.1/evt

=> Increase by 30% in digi/evt for the other detectors, increase by 400% for mSTS
=> Probably quite some central events in the mix (higher multiplicity in all detectors) but

• either STS reacts differently/stronger to them
• or there are on top some real "monster events" affecting only STS

=> To differentiate probably one would need to make a set of plot mul/evt STS vs mul/evt XXX to see if there is a single correlation or two classes of events