Description

This is a refactor of some parts of autoimport. It unifies cache generation between modules and resources and other methods.
I merged some changes from the CI branch regarding autoimport. I don't really intend to merge this branch because I intend to move autoimport to its own package/repository for a couple reasons:

1. Since I'm responsible for it, I'd be able to maintain it myself
2. It can be more easily integrated in projects like Jedi and pylsp without relying on the rest of rope.
3. I can use more modern tooling/items more easily
4. Its easier to maintain, since I'd be able to implement the entire rope API atop a much smaller subset
5. Rope isn't really a completion library

I'd take one of the following approaches:

1. Take this branch, move autoimport to its own repository, and later use that in rope, replacing the sqlite3 implementation while (at least mostly) preserving compatibility. Some of the refactors here make this easier. The other library would be kept as an optional dependency for the sqlite implementation.
2. If that isn't an option, consider merging this PR (after add windows and mac CI #481, sorry for making it messy) and link the new version in documentation. I may remove rope-specific APIs in the new implementation.