feat: loading featurizer

[FMcil]

Hi Kevin!

I added a featurizer that calculates uptake values based on RASPA.

It is heavily based on the Henry featurizer. I would very happy if someone could check over the RASPA simulation script in loading.py before this is pull request is accepted.

The simulation script is based on an example in the RASPA2 repo.

FYI I received multiple fails in tox unrelated to this change. There were no issues using pytest on test_henry.py and test_loading.py

[kjappelbaum]

Thanks for this addition and sorry for the long delay in reviewing it!

[kjappelbaum]

do you have a clue if the linting CI fails because of a version mismatch? In the longer term, we should migrate mofdscribe to ruff, but I'd probably try to still make the action pass now for consistency

[FMcil]

do you have a clue if the linting CI fails because of a version mismatch? In the longer term, we should migrate mofdscribe to ruff, but I'd probably try to still make the action pass now for consistency

I believe linter fails then triggers tox to exit with failures. I am not sure why linting is only a problem here (and has not been caught previously with other PRs to main).

On the elipses failure, looks like black reformats elipses on one line then the linter fails: PyCQA/flake8#1926

I added pass instead of elipses.