add validator report

[lkstrp]

Adds Validator CI. See the report below.

• It is triggered by any new commit in pr.

• Runs on a self-hosted github runner and solves on z1, so basically any configuration can be set. No restrictions. It just takes a while to update the comment if you choose a computationally intensive config.

• Compares the base branch (main) with the latest commit in the pr branch. So runs both, but also caches (in addition to snakemake caching) based on commit hashes. - Edits one main report comment when new commits are pushed to the repo, to avoid spamming.

• Set all settings in workflow file (mainly which plots to show, pre-commands, environment selection, etc.)

• Some things which are missing:

  • Better comparison (use n.statistics)
  • Handle environment updates
  • More file filters to avoid unnecessary runs
  • Concurrency

Also have a look at the Wishlist and see action repo to create any issues. This will be moved to the PyPSA org at some point.

[lkstrp]

See #1295