Add UKACM & GACM tutorial: Quantifying Uncertainty due to heterogeneous material fields

[reginabuehler]

Description and Context:
What and Why?

This PR includes the final tutorial from the UKACM & GACM Autumn School workshop into QUEENS.
Huge thanks and full credit to @gilrrei, who developed and authored the original tutorial.

The fourth tutorial is added into the QUEENS documentation as 4_quantifying_uncertainty_due_to_heterogeneous_material_fields and tests this by including it into the documentation build of the CI pipeline.

The content of the tutorial was peer-reviewed during the development for the workshop, but I would appreciate someone taking a look at the content again.
I'd also appreciate someone checking the doc strings and type hints of the random_field.py module since I am not familiar with that module.

To reduce code redundancy the utility function used both in the 3rd and 4th tutorial was refactored and tutorials turned into a package. The import is ensured by small changes in the Github workflow as well as the actual Jupyter notebook. One option to eliminate those small changes might be to refactor the tutorials/utils.py into src/queens/utils/ if desired.

Commits will be squashed into one commit after addressing the review comments.

Notes during development

• Improve docstrings and type hints
• Fix docstring in 3rd tutorial and eliminate code redundancy
• Check local run
• Adapt text for documentation/online tutorial
• Fix import of tutorials.utils

Refactoring of utility and plotting functions:

• It is necessary to make sure the package tutorials can be imported locally and also in the CI. Can this be done in the GitHub actions workflow or do I need to add to sys path for docs? Apparently, in GitHub actions workflow is sufficient. Maybe put utility function in src/queens/utils?

Related Issues and Pull Requests

• Closes
• Related to Tutorials #58, follow-up of PR 287

Interested Parties

Note: More information on the merge request procedure in QUEENS can be found in the Submit a pull request section in the CONTRIBUTING.md file.

[gilrrei]

Thanks for the work. The docstrings and typehinting of the random field class lgtm.

[gilrrei]

I think we should use the same input file(s). I don't see I reason why we have to have it twice.