Prism mapn combine

[beezee]

• [] prisms can be derived for all arity Cop types which may be useful for optionally extracting a member
• mapN can be defined in terms of a Functor constraint on the F in a CopK[F] or ProdK[F] for all Ns within a given arity (done minus Functor awareness, might be overkill)
• [] "combine" can be given for (A, B) where B is a Monoidal Product) and A has an Inject to B.