Make changes to repo so it can be public

[bendnorman]

This PR:

• Removes PUDL Datastore and ZenodoFetcher support now that 2020 lbnl queue data is in git.
• Removes EIA API key.
• Redacts sensitive information in EIP data.
• Adds some data licensing language to the README.
• Adds an MIT license to the repo.

Ok, I removed the notebook outputs and the API key. I used bfg to remove default.env from the git history, which duplicated a lot of commits which is this PR is trying to merge in hundreds of commits. Apparently, duplicate commits are a product of git history fixing tools.

In retrospect, I should have refrained from using bfg until the sensitive information was merged in so this PR didn't contain hundreds of commits. I think we should merge the notebooks with the cleared outputs and redacted data into dev and main and then run bfg.

[bendnorman]

Thanks for the tip! Will use git mv in the future.