Fix class names in `chaos_domain.py`
Fix indexing of CHAOS actions and extensions
Fix referencing in CHAOS Domain
Change API from single-page to files [MAJOR UPDATE]
Remove unused `module` option from CHAOS domain
Add style for sphinx `rubric` directive
Fix `ObjectRelation` documentation for v4

The current ObjectRelation implementation, has `Create` instead of `Set`
and doesn't support metadata annotations.
Add section about git structure to README

and add `update-branches.sh`