[Chore] Remove deprecated types and functions

Description

Problem: we just cut a new release. It makes sense to remove things that are deprecated, while we didn't deprecate something else, to save us some trouble next release.

Solution: do that.

Related issue(s)

Resolves None

✅ Checklist for your Merge Request

Related changes (conditional)

• Tests (see short guidelines)

  • If I added new functionality, I added tests covering it.
  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

• Documentation

  • I checked whether I should update the docs and did so if necessary:
    • Root README and other README.md files
    • Haddock
    • docs/
  • I updated changelog files of all affected packages released to Hackage if my changes are externally visible.

Stylistic guide (mandatory)

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• My code complies with the style guide.