refactor: eliminate inheritance from object

[aucampia]

This change removes the redundant inheritance from object (i.e. class Foo(object): pass) that is no longer needed in Python 3 and is a relic from Python 2.

Checklist

• Checked that there aren't other open pull requests for
  the same change.
• Checked that all tests and type checking passes.
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.

[coveralls]

Coverage: 90.831% (-0.0004%) from 90.832% when pulling 1ec08fc on aucampia:iwana-20230409T2118-no_object_inherit into 4940798 on RDFLib:main.

[aucampia]

/wsp review

[what-the-diff]

PR Summary

• Updated class definitions to new style
  Changed the way classes are defined to adopt the more modern style for readability and consistency.
• Removed doc from classes
  Cleaned up unnecessary doc attributes from various classes.
• Added type hints for better code clarity
  Introduced type hints for certain functions and methods, such as _runtime.
• Updated test classes for consistency
  Made updates to test classes like SerializerTestBase and test_serializers/test_prettyxml.py, to maintain uniformity across the codebase.

[aucampia]

Merging without review, as this does not change runtime behaviour.