Wagtail-f-richtext

- removes poetry
- Add loading the richtext filter in a template
- Fix typo in README.md
- update for wagtail 6.0, 6.1 & django 4.2 & 50
- update for python 3.9, 3.10, 3.11 & 3.12
- drop python 3.8 testing
- fix actions using mysql image

- Refactor everything

Added

- Wagtail 3/4 support

Changed

- Developer setup and tooling

Removed

- Example App

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