[mlir][ods] Add materialize derived attribute method

Summary:
Generate method to generate a DictionaryAttr with attribute values of
derived attribute. If a conversion back from the derived attribute C++
type to Attribute is not defined, then attempting to materialize such an
op's derived attributes would result in runtime failure.

This allows to treat derived attributes and attributes of an op in more
uniform manner where needed. The derived attributes are not added to the
operation but returned as new attribute instead.

Differential Revision: https://reviews.llvm.org/D78302