ci: misc ci updates

[consideRatio]

• ci: configure pytest via pyproject.toml
• ci: don't have two separate release jobs
• ci: stop using deprecated codecov python CLI
• ci: test against python 11
• ci: misc refactoring

[consideRatio]

I'll go for a merge since this is just a PR impacting the CI system and we struggle to keep up reviewing PRs overall currently!