Inconsistency in code gen for constructor params of Python overlay resources

[praneetloke]

Related to pulumi/pulumi#4464 and #1072.

The input properties for each of the overlay resources are not consistent among themselves and not consistent with how the Pulumi schema-based code gen would generate them. I don't know if this is something we can actually fix since overlay resources aren't really schematized, but wanted to track the differences somewhere. If these are things we can bring alignment on, we can avoid having manual exclusions to generate docs for these.

• The opts param ordering is not consistent. Sometimes appears after all input properties, and other times not. Even then it is out-of-sync with how the schema-based code gen would generate it.
• Between the NodeJS and the Python SDKs, the params of the apiextensions.CustomResource are not the same.
  • For instance, in Python there is an extra input property called spec, which is not accepted as an input prop in the NodeJS SDK.
  • The othersFields property available in NodeJS isn't there in the Python SDK. I am not a Python expert here, but I would have expected to be able to pass a dictionary similar to the map in the NodeJS SDK.

[praneetloke]

cc @lblackstone