Part0 and part1 Edits from Madison Reviews

[mnfienen]

Most of this PR is fixing typos and minor wording issues in the notebooks based on review from USGS Upper Midwest Team. A couple bigger issues that may warrant review:

• updated pyemu and flopy dependencies to today's develop branch of both. This got rid of a couple annoying warnings but did require an edit of a parameter name as PstFrom had had a minor change. I reran all part 1 notebooks with no issues.
• consistent with README.md I only numbered the first 3 notebooks in part 0. The others are just, e.g. part0_intro_to_geostatistics.ipynb to remove the implication that they should be run in order prior to part1. This was confusing to the reviewing group.
• Tried to clarify a bit in README.md regarding organization of the notebooks, again focused mostly on part 0.
• Also added the official USGS release reference to README.md but if it's better to focus on the GMDSI URL that's fine. Just that the USGS release has a DOI which may serve as another way to track refs and impact.
• Finally, I merged in main branch so this should be ready to go following review

[rhugman]

Thanks @mnfienen (and the review team!).

[mnfienen]

thanks @rhugman ! I merged this