Remove DSTWriters and DaVinciAssociators
I don't think they are still used.
However there are mentions of
CompositeParticle2MCLinks
NeutralPP2MCP
Particle2MCChi2
Particle2MCLinks
Particle2MCWithChi2
in LHCb, which should be cleaned if this MR goes through.
Edited by Patrick Koppenburg