Add ID and ABSID ThOr functors

Created a dedicated issue for the part of #170.

Particle_v2 already has ParticleIDs container (https://gitlab.cern.ch/lhcb/LHCb/-/blob/master/Event/PhysEvent/include/Event/Particle_v2.h#L135), so adding ID functor must be ~trivial.

One difference between v1 and v2 Particles that I've noticed: in Particle::v1, the particleID() method returns LHCb::ParticleID&, while in Particle::v2, the pid() accessor returns int. I suspect that dealing with LHCb::ParticleID is more correct (e.g. it overloads == operator such that one can check ID==211 or ID=='pi+'). I'm not sure how to best deal with that in v2. Should we leave std::vector<int> in the ParticleIDs container and then somehow convert it to the vector of LHCb::ParticleID on-the-fly?