Refactor: Update CI workflow

[gampnico]

Two potential updates:

1. Packaging CI
   As discussed, similar to OGGM's workflow. Should this also run on PRs?

2. Streamlining installation requirements
   Similar to OGGM, some optional dependencies require manual installation on the user's part.
   Could we remove the yaml files under ci/requirements and manage them via pyproject instead? E.g. py3(XX)-all.yml are all identical except for the Python version. Something like:

optional = ["cartopy", "rasterio", ...]  # all of salem's optional dependencies
tests = [salem[optional]", ...]  # equivalent to py311-min.yml
dask = ["salem[tests]", "dask"]  # equivalent to py311-xr.yml
dev = ["salem[tests]", "salem[dask]", ... ]  # equivalent to py3(XX)-all.yml

[fmaussion]

1. Not on PRs I think? Why would this be useful?

2. Sound good to me

[gampnico]

1. Not on PRs I think? Why would this be useful?

Sorry, I got this mixed up with something else.