CI: introduce groupings for notebooks to address needs for much never version requirements #109
Description
Some of the notebooks require brand new releases for their functionality (e.g the ones using HATS) and this doesn't fit well into the approach of supporting a wide range of versions and ensure that those are tested. So the CI will need to be chopped up and use different environments for the more generic content and the specialized ones as currently we use the assumption that everything runs in one shared environment.
xref #108