feat(docs): Improve cddl definitions

[stevenj]

Description

Improves how CDDL Definitions are made, by allowing them to be made into a controlled file first.
This is a big change because it refactors docs to make it easier to have docs which generate docs, and everything
still generate and validate correctly.

It also makes everything more OO, which should help with maintenance and reducing strict interdependencies
between the specification and the documentation generators.

Changes diagrams to be generated with Graphviz to give us better control and more features.

Related Issue(s)

Lots of planning ones, as these are specification related changes.

Description of Changes

• Refactor the way docs are created.
• Make creating CDDL files easier and more re-usable.
• Make docs that create dependent docs easier to do/maintain.
• Make using relative file includes in mkdocs work by using latest upstream cat-ci.
• Add strict python formatting and linting, because we are introducing a lot of python code now with this.

Breaking Changes

Its self contained, and nothing else consumes the signed_docs.json spec yet, so its changed but it doesn't matter.

Please confirm the following checks

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream module

[stevenj]

This PR is not ready for merging yet, still WIP. But feel free to review.

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 317/317}$ | ${\color{red}Fail: 0/317}$ |

[Mr-Leshiy]

LGTM