Add new index table

[JazSpaz24]

Description of changes:

Add a new index notebook for key metrics that includes new plots and tables

All PRs Checklist:

• [x] Have you followed the guidelines in our Contributor's Guide?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] Have you made sure that the pre-commit checks passed (#8 in Adding Notebooks Guide)?
• [x] Have you successfully tested your changes locally when running standalone CUPiD?

New notebook PR Additional Checklist (if these do not apply, feel free to remove this section):

• [x] Have you hidden the code cells (#8 in Adding Notebooks Guide) in your notebook?
• [x] Have you removed any unused parameters from your cell tagged with parameters? These can cause confusing warnings that show up as DAG build with warnings.
• [x] Have you moved any observational data that you are using to /glade/campaign/cesm/development/cross-wg/diagnostic_framework/CUPiD_obs_data and ensured that it follows this format within that directory: COMPONENT/analysis_datasets/RESOLUTION/PROCESSED_FIELD_TYPE?

[TeaganKing]

This is dependent upon #210

[TeaganKing]

#210 has been merged; changing to open PR & will test/review shortly.

[TeaganKing]

While this is at the heart of 'key metrics', we could also pull this into the external diag packages example since both ADF and ILAMB are in that example. Thoughts? It may also be worthwhile adding a summary at the top of each of the tables describing what they entail. Otherwise, this is ready for review.

Actually, one other larger question here: do we want to use summary_tables.ipynb as the default landing page only if ADF and ILAMB have been run? Otherwise it may look a bit drab and possibly confusing with empty space instead of table output....

[TeaganKing]

TODO:

• [x] update logic in generate_cupid_for_cesm_case to use summary_tables.html instead of index.html if running ILAMB or ADF or LDF.
• [x] bring in table from LDF
• [x] add into external diag packages
• [x] merge conflicts
• [x] test out generate_cupid_for_cesm_case with some external diags turned on
• [x] test out generate_cupid_for_cesm_case with no external diags turned on

[TeaganKing]

Closing this since #237 is the same thing with fixed merge conflicts. This just got very unwieldy...

[TeaganKing]

Once CUPID_STOP_N and CUPID_BASE_STOP_N are available in CESM, generate_cupid_for_cesm_case should work fine. I tested this by manually setting those values as well as Boolean values for CUPID_RUN_LDF and CUPID_RUN_ILAMB

[TeaganKing]

@mnlevy1981 this is ready for your review.