Frequenz Repository Configuration Release Notes

Summary

mkdocs
- The script docs/mkdocstrings_autoapi.py was moved to docs/_scripts/mkdocstrings.py.
- Note that now code annotations will be numbered. This is useful to hint about the order one should read the annotations.
- The following files were renamed to keep the documentation directory clean for documentation files:
  - docs/css -> docs/_css
  - docs/overrides -> docs/_overrides
  - logo.png -> docs/_img/logo.png
- You might need to remove old mike version aliases. Probably removing next should be enough:
```
mike delete -p next
```
  You can use mike list to list all versions and aliases.
CI
- You can now make your branch protection rule only require the "Test with nox" CI job to pass. All the matrix expansions will merge into it, so there is no need to change branch protection rules if matrix elements are added or removed.
- Dependabot now will check for updates monthly and on a random day and time.
The src/conftest.py file was moved to src/<project_path>/conftest.py.

This is to leave the src directory free of any files, so it is easier to navigate using auto-completion and GitHub file browser.

mkdocs
- New markdown extensions: def_list / task_list and footnotes.
- New mkdocs-macros extension.
- Show inherited attributes in the documentation.
- Make code annotations numbered. This is useful to hint about the order one should read the annotations.
- Add a navigation footer to show previous and next pages. This is specially useful when reading the documentation in a mobile device since the navigation bar is hidden.
- Updated dependencies.
- We use a new mike versioning scheme:
  - Versions now have a title with the full tag name for tags and includes the (short) commit SHA for branches so users can know exactly which version they are reading.
  - Pre-releases are now published too as vX.Y-pre. They have aliases to point to the latest pre-release in a major (vX-pre) and the absolute latest pre-release (latest-pre).
  - All branches are now published with their own version as vX.Y-dev. They have aliases to point to the latest version in a major (vX-dev) and the absolute latest version (latest-dev). This means the old next becomes latest-dev.
CI
- Add CI job to test package installation on multiple platforms (amd64 and arm64).
- Add CI job to run the tests in arm64.
- Add a CI job to join all nox runs, so only one branch protection rule needs to be used.
- Dependabot now will check for updates monthly and on a random day and time. This is to avoid all repositories updating at the same time.

mkdocs
- Fixed mermaid diagrams not rendering in the documentation.
- mypy ignores for cookiecutter have been removed. They should have never be there as generated projects don't use cookiecutter.
- mypy overrides now are applied to API projects too.
- Now the latest mike version will point to the highest stable version available, not the latest version published.
Dependabot branches are now not tested for push events, as they are already tested by pull events.

Full Changelog: v0.6.2...v0.7.0