Create description annotations for vectorized UDF

Vectorized UDFs should technically be close to the same as normal UDFs, but that is not guaranteed. For example a standard UDF might have multiple overloads that the vectorized version does not.

When users run things like 'describe function' they may not be getting the correct information depending if they are in vectorized mode or not.

ehans I assigned this to you feel free to unassign it, but I think we need some internal documentation for vectorized UDFs.