Remove Network model

[savente93]

Issue addressed

Fixes #817

Explanation

We currently don't have an implementation or a model to base a potential implementations on, so it doens't make much sense to keep this around until we do. Therefore it's better to remove it it and work on it when we have an actual use case. As we haven't been touching the main documentation throughout v1 I haven't updated it there either, we will tackle that when we adress the documentation more directly .

Checklist

• Updated tests or added new tests
• Branch is up to date with main
• Tests & pre-commit hooks pass
• Updated documentation if needed
• Updated changelog.rst if needed
• For predefined catalogs: update the catalog version in the file itself, the references in data/predefined_catalogs.yml, and the changelog in data/changelog.rst

Additional Notes (optional)

Add any additional notes or information that may be helpful.

[hboisgon]

LGTM!