Generalise MAP_INPUT functor (for MC association), add PARTICLE_ID, OBJECT_KEY and BKGCAT

This MR consists of the following:

• Update MAP_INPUT functor to take in any type of relation table. It now allows for partial template deduction (since it is a templated function now). The template parameters can be passed by users via RelationsType or can be requested to be obtained from TES location via get_templateparams_from_tes = True (this only works if an entry already exists in dictionary tes_to_templateparams). Example usage for MC association is here.
• Add three new functors: PARTICLE_ID, OBJECT_KEY and BACKGROUND_CATEGORY(Relations=...). Hierarchy related functors to follow (see !2652 (merged)).

The tests for the new functors exists in DaVinci!621 (merged)

Dependent on MR: LHCb!3367 (merged)

Is related to issue (https://gitlab.cern.ch/lhcb-dpa/project/-/issues/145).

Also related to MR (but not dependent on): Phys!1029 (closed), Analysis!851 (merged), DaVinci!621 (merged), !2652 (merged), Analysis!846 (merged)

FYI: @graven , @gunther , @mferrill , @powen