refactor: remove deprecated stuff

[mdevolde]

refactor: remove deprecated stuff

Why the pull request was made

To remove deprecated functions/classes to be able to publish the next breaking release soon.

Summary of changes

• Remove deprecated functions/classes.
• Remove useless tests (linked to old custom deprecated decorator)

Screenshots (if appropriate):

Not applicable.

How has this been tested?

Applied local tests.

Resources

Not applicable.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (changes to documentation only)
• Refactor / code style update (non-breaking change that improves code structure or readability)
• Tests / CI improvement (adding or updating tests or CI configuration only)
• Other (please describe):

Checklist

• Followed the project's contributing guidelines.
• Updated any relevant tests.
• Updated any relevant documentation.
• Added comments to your code where necessary.
• Formatted your code, run the linters, checked types and tests.