Add (mutable) type getters to edm4eic::vertex

[osbornjd]

The vertex object has a type object that is currently not rigorously defined. In the future it would be beneficial to have some concrete types that a vertex could be (e.g. primary, secondary, background, other...). Adding getters with bit shifting will allow for easier type identification, similar to that in edm4hep::MCParticle.

Describe the solution you'd like
Something similar to https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L188-L220

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