Add the serialization logic for the `WCS` wrapper classes in `ndcube`

[ViciousEagle03]

Write converter and design schema for the WCS wrapper classes

• [x] ResampledLowLevelWCS
• [x] CompoundLowLevelWCS
• [x] ReorderedLowLevelWCS
• [x] Update the schema and converter of NDCube to include these WCSes as the underlying wcses.

Tests

• [x] Add tests for the roundtrip serialization of wrappers with underlying wcs as gwcs.WCS.
• [ ] Add tests for the roundtrip serialization of wrappers with underlying wcs as astropy.wcs.WCS.