Generate somewhat cleaner TypeLists

[NyxCode]

See #291, #289

Goal

Generate TypeLists containing less duplicates. This speeds up generation of imports, and avoids rustc recursion limits.

This does not aim to fix the "recursion limit" problem completely. Before, ~128 types caused the issue, while now, it'd only be caused by ~128 unique types.

Changes

• Re-implement Dependencies to manually track "direct", "transitive" and "generics" dependencies, only generating rust code at the very end.

TODOs

• Cleanup implementation
  • The current impl is kinda messy. I used Rcs to avoid excessive cloning, but a better data structure would probably help here
• Explore if generating a "perfect" TypeList is a cleaner approach
  • I think this can be implemented on top of most of these changes though, only needing to alter the ToTokens impl

Checklist

• I have followed the steps listed in the Contributing guide.
• If necessary, I have added documentation related to the changes made.
• I have added or updated the tests related to the changes made.

[NyxCode]

closing in favour of #293