ATR-22003, ATR-21589, ATR-21822 add functionality for splitting signatures into multiple alignment groups; add HLT_mu20_ivarmedium_mu8noL1_L1MU20
Adds an 'alignmentGroup' property to the ChainDict (and ChainPart dict). This is set using the signature and the 'extra' property.
I suggest this is where we put in 'probe' or 'lowpt' or any such string later, when we want to run a second instance of the algorithms (but in that case the algorithms/hypos/sequences will also need renaming - muXnoL1 has its own sequences).
Automatically determines the ordering of signatures from the OrderedDict in MenuAlignmentTools - no more hardcoding elsewhere.
Fixes a bug I did not realise existed - before, alignment would have failed in the case where empty steps needed to be inserted in the middle of a chain, but we did not have any such chains in the menu. This now works (e.g. for mu20_ivarmedium_mu8noL1).
Also fixes a bug in triggerSummaryCfg, where the sorting of hypos by default python sort put steps 10-19 before steps 1-9 and resulted in a ComboHypo from the incorrect step being used for the final decision, for chains > 9 steps long with > 1 combo hypo.
In principle, three-signature combined chains should work now (but I have not tried this).
ART tests are fine and the references are updated, ctests pass.
Closes ATR-22003.