Make it possible to select / view only certain collections for a given view

[tmadlener]

Currently we always display all the objects of a given type (or types if we have a multi-type view). It would be nice if we had the possibility to choose which collections to display and give users an easy way to select them, e.g. via a drop-down menu with check boxes / toggle buttons.

As an easy to use example for developing we can use our wzp6_ee_mumuH_ecm240_CLD_RECO.edm4hep.json file which has multiple MCParticle collections which overlap by quite a bit so that the number of displayed particles is almost double of what we would want in the end.

I think once #70 is done, this could potentially even be done via the same mechanism, i.e. simply use a filter on the collectionID to get rid of the objects that we don't want.