Add automated caching of public datatypes

[FreshAlacrity]

Using GitHub API or Actions with a request from either the Navigator or the Google Sheets doc

• [ ] Function to import, merge, and then export the public projects spreadsheet data to JSON
• [ ] Support exporting to cache when
  • [ ] Manually saving changes to the sheet
  • [ ] As autosave option (along with or as an alternative to saving to sheet)
  • [ ] Prompted by Google Sheets edit using a PUSH request

[FreshAlacrity]

See also #60