Add schemas for some astropy.modeling models

As I am reading through this and trying out pyasdf I tried creating schemas for `astropy.modeling` models commonly used for WCS transformations. So here they are.

I think only models which don't define an analytical inverse need the `inverse` definition in the schema so only the polynomials have it here. If this is acceptable I'll add the rest of the polynomials.
For cases like "this actually represents an array of polynomials" I agree there should be some more efficient way to write that than putting a polynomial model per pixel in the YAML.  I think there should be some explicit way of representing that though.  "param_dim" does not say to me "this is actually a large collection of parameters for the multiple instances of the same type of model".