AFMReader refactor update

[ahobbs7]

Updates the loading of AFM files to expect an AFMLoad object from AFMReader rather than the previously returned tuple or dict object.

Note: this pull request should not be merged until the pull request for AFMReader has been merged into main.

• Existing tests pass (some tests have been updated to align with new topostats).
• Documentation has been updated and builds. (No changes necessary)
  • docs/usage/configuration.md
  • docs/usage/data_dictionary.md
  • docs/usage/advanced.md and new pages it should link to.
• Pre-commit checks pass.
  No new functions or methods so the following or not necessary
• New functions/methods have typehints and docstrings.
• New functions/methods have tests which check the intended behaviour is correct.

[ahobbs7]

Tests currently fail due to the AFMReader updates being in PR state and hence the current pypi release being used instead. The dependencies may want to be updated to installing from the main branch with git (once the PR is merged) or a pypi release may need to be made for AFMReader before merging this branch.