[mlir][ods] Default-valued parameters in attribute or type defs

[mlir][ods] Default-valued parameters in attribute or type defs

Optional parameters with `defaultValue` set will be populated with that value if they aren't encountered during parsing. Moreover, parameters equal to their default values are elided when printing.

Depends on D118210

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D118544