Update user flows based recent insights for the Kickstarter campaign

[bobness]

Requires https://github.com/bobness/inspect-service/pull/81 && https://github.com/bobness/inspect-service/pull/82

• [x] Using Inspect instead of my Gmail to more conveniently save articles and share with others later
  • [x] Change is_favorited to !is_public
  • [x] Move snippet creation out of SummaryScreen into its own screen to avoid confusing conditional blocks
• [x] Emphasize the importance/relevance/ABSURDITY of the article when notifying/sending digests to followers
  • [x] Implement daily/weekly digests
  • [x] Implement registering and logging in via the web, including signing them up for digests when they do
  • [x] Add reactions and maybe comments to digest emails
  • [x] Implement option to enable/disable digests in the app
  • [x] Change green text to include checkboxes for snippet(s), reaction, comment(s) and why they are needed
  • [x] Separate notification and email digest API routes so updating a summary doesn't add it to digests (!)
• [x] Change green text above publish buttons to be more about article quality checking