407 add workflow addon dev docs

[MustafaJafar]

Changelog Description

• Add dev docs for AYON Workflow Addon
• Rearrange the integration list in the sidebar

Testing notes:

1. go through docs and approve if it make sense.

[MustafaJafar]

For information, this dev docs is based on the current docs folder inside the ayon-workflow addon + my personal testing and exploration for the addon. my goal in this dev docs to make it direct and minimal that's why I didn't explain some topics in further details as the docs folder in the ayon-workflow addon. also, I didn't mention legacy node creation.
It's worth mentioning that the docs folder from the addon will be part of the addon api reference generated by mkdocs. (which is in progress).

This PR was made around Reimplement all nodes as classes PR.

[MustafaJafar]

This link doesn't exist yet. it'll be once the mkdocs PR on ayon-workflow repo is merged.