Backend functionality for retrieving based on warming levels approach

[nicolejkeeney]

Description of PR

This branch of climakitae needs to be run with the corresponding branch of the same name in climakitaegui

Backend and front-end functionality added for retrieving based on warming levels or time based approach.

Eventually I think the goal is to move away from the warming levels explore module (?) since this functionality essentially duplicates that functionality within DataParameters object. Will need to discuss with the team what to do with the existing GUI functionality from warming.py since I believe having two similar but slightly different warming levels objects/functionality (i.e. ways to access data by warming level) will confuse users.

Notebook documentation should be updated to reflect this new functionality!

In a separate PR, I will update the functions in the climakitae_direct_data_download.ipynb notebook to reflect these new options and allow for users to use this approach without using the GUI or directly modifying the selections object.

Summary of changes and related issue

Lots of changes were made; I'll try to summarize as best as I can here.

1. Several new attributes were added to the DataParameters object to allow for retrieving based on warming levels: DataParameters().approach, DataParameters().warming_levels_window, DataParameters().warming_levels_months.
2. The global warming levels table (gwl_1850_1900_file) was added as an attribute to the DataInterface object, allowing the table to be passed around easily instead of read in by individual modules
3. The selections GUI was changed to reflect the new options
4. A new module added in utils "warming_levels.py" with the warming levels helper functions.

Relevant motivation and context

Part of a larger effort to incorporate warming levels into AE stuff.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] This change requires a documentation update

Definition of Done Checklist

Practical

• [x] 80% unit test coverage
• [x] Documentation
  • [ ] All functions/adjusted functions documented in the readthedocs.
  • [ ] Documentation is pushed
• [x] Complex code commented
• [x] Naming conventions followed
  • [x] Helper functions hidden with _ before the name
• [x] Context of function is clearly provided
  • [x] Intent of function is provided
  • [x] How to test, so that it is not siloed on scientists and anyone can review
  • [x] Appropriate manual testing was completed
• [ ] Any notebooks known to utilize the affected functions are still working
• [x] Linting completed and resolved

Conceptual

• [ ] Doesn't replicate existing functionality
• [x] Aligns with general coding standard of existing functions
• [x] Matches desired functinonality from users/scientists

[nicolejkeeney]

WL integration step 2: backend data retrieval

[claalmve]

Looks good to me! I just left a few small comments, but otherwise, the functionality of this PR looks great! Great work on such a big change in our codebase and including WL's in a much more consolidated format.