Main change: this provides an optional possibility to align the geometry before running the overlap checks, with the same method as done for the reco.
Done for now in a crude way by locally cloning the FairAlignmentHandler with some name collision guards, as it is otherwise hidden in FairRun which reverts the alignment before outputting the geometry (therefore hiding any overlap due to alignment).
Triggered by what happened in !1183 (merged) that an aligned geometry was leading to some crashes in the reco (see also issue #2939).
Should allow to catch cases of overlaps created by too coarse alignments or alignments applied to the wrong level in the geometry (e.g sensor instead of ladder), for as long as it is done by hand. When we switch to automatic alignment, this should not happen anymore (provided the volumes boundaries/constraints are properly set).
This new functionality is meant to be run by hand, not through the CI, and the main usage will be to allow to send the ball back to the detector experts when they report problems in reco which are in-fine due to this kind of broken alignment. One example for a known case in mCBM is however provided for the Nightly/Weekly builds to ensure it is not broken.
Additional tuning: Expected overlaps from https://cdash.gsi.de/testDetails.php?test=15554039&build=401452
Probably of interest to @se.gorbunov and @e.clerkin
Refs: #2931