Add to installation the headers which were missing for the standalone installation operation
of ROOT macros loading the mCBM 2018 library.
Tested with the macro/beamtime/mcbm2020/MonitorT0.C
macro and the chain run_transport.C -> run_digi.C -> run_reco.C
in macro/run
related to redmine issue refs #2017 and MR !340 (merged)