21.9: add DetFlag option to allow configuration of MBTS

Add DetFlag option to allow configuration of MBTS, allowing ITK jobs to run without it (and making this default ITK behaviour).

This allows currently-defined "step 3.0" layouts to run. Without these changes, it is necessary to run either MBTS or HGTD and part of the calorimeter, and neither are defined for these geometries. TBD how this will be defined for future ITK geometries - likely HGTD will no longer be part of calo, but MBTS will likely also not be present.

NB this technically changes the simulation results of the step 2.2 tests (RunUpgradeTests.py -s), since previously we were running MBTS there in the simulation, but it also repeatedly caused issues in reconstruction when we tried to include pile-up. Therefore, it seemed to make sense to also disable MBTS simulation there. All other tests outputs (RunUpgradeTests.py, RunTier0Tests.py, RunTier0Tests.py -s) remain unchanged.

INFO     All s1 athena steps completed successfully
INFO     ---------------------------------------------------------------------------------------
INFO     Running s1 Frozen Tier0 Policy Test on HITS for 10 events
INFO     Reading the reference file from location /tmp/nstyles/clean_run_s1_4575cd40-6e59-4f65-889e-7a0a3c6ac4af
ERROR    Py:diff-root      WARNING the following variables exist only in the old file !

ERROR    Py:diff-root      WARNING  - [TileHitVector_p1_MBTSHits]

ERROR    Your tag breaks the frozen tier0 policy in test s1. See run_s1/diff-root-s1.HITS.log file for more information.
INFO     -----------------------------------------------------

FYI @asalzbur @cohm @lmijovic @goblirsc @npetters @hhayward @nreadiof