v0.3.0 - Add ParticleID, remove momentum, add vector

Some small changes to help usability:

• Add ParticleID, which is a combination of Cut2D and NuclearData to the nuclear module. Previously this was in Spyral, but it makes more sense to be here.
• Remove momentum module, and replace with a dependency on the vector package. They support way more advanced vector-analysis than what we could support, so make for a much improved solution over our custom one.

Documentation is updated and dependencies are somewhat cleaned up for the development side.