Shared prime group trait for projective and affine points #43
Description
It would be nice to have a shared trait over projective and affine points that signifies if they belong to a prime group or not.
Currently the prime group traits are split in PrimeCurve, PrimeCurveAffine and PrimeGroup, my understanding is that affine points can only implement PrimeCurveAffine, therefore having no shared trait between the too.
Therefor I would like to propose a marker trait that can be implemented for both.
Happy to make a PR if somebody can suggest me a name, IANA cryptographer and don't feel 100% comfortable with all the terminology used here.