Add hlt2+sprucing bandwidth test on pp+SMOG simulation

Add test infrastructure for pp+pAr MC (SMOG worst case scenario in terms of bandwidth/rate, see details in !411 (closed)).

Supersedes (well, includes) !411 (closed) . At least locally test goes fine.

To be tested with lhcb/Moore!3563

Also related to lhcb-core/LHCbNightlyConf!1231

Closes https://gitlab.cern.ch/lhcb-dpa/project/-/issues/295

cc @oboenteg @kmattiol and many thanks to @rjhunter for the help in troubleshooting