Implement helper method to find module path of value

[Jake Howard]

Finding the module path for where a given class or function is defined is functionality used in a few places across the Django codebase. Whilst in the majority of cases, f"{val.__module__}.{val.__qualname__}" is enough, there are some cases it's not.

As part of #35859, a few more cases of this pattern are being added to the codebase. I think we're now at the [point ​https://en.wikipedia.org/wiki/Rule_of_three_(computer_programming)] where it makes sense to extract this out to a helper function somewhere in django.utils. The implementation in django.migrations.serializer.TypeSerializer seems to be the most robust, however will want some more thorough testing based on different input types.