Support wildcard types within parameter / return types in library modeling

[msridhar]

This includes Foo<?> and also upper and lower bounds. We need the strings in the astubx files to match the source syntax for these types (see, e.g., here or here. We should support in both JarInfer and the generator from source code.

[msridhar]

We need to do this before regenerating the astubx for Android SDK 31.