Add cypress tests for important testable scenarios

[mmcknett]

End-to-end happy path test flow:

1. Create an account
2. Log out
3. Log in with the account just created
4. Create a draft a. Check that the draft exists on firebase
5. Delete the draft a. Check that the draft doesn't exist
6. Make a note and submit it a. Make sure the note appears on the page. b. Check that firebase has a note, too.

Tasks:

• [x] Integrate with Firebase Auth emulator
• [x] Add cypress
• [x] Run app with auth emulator connected when cypress tests are run, whether the UI is opened or it's headless.
  • Make sure to use the mode where draft save is 1s instead of 5s.
• [x] Set up github actions so PRs & main run the e2e tests as a check prior to deployment.

Resources:

• Cypress GitHub Actions doc: https://docs.cypress.io/guides/continuous-integration/github-actions
• Installing Cypress: https://docs.cypress.io/guides/getting-started/installing-cypress
• Authoring the first test: https://docs.cypress.io/guides/end-to-end-testing/writing-your-first-end-to-end-test

[mmcknett]

My initial test plan ended up looking like:

End-to-end happy path test flow:

1. Create an account
2. Log out
3. Log in with the account just created
4. Create a draft a. Check that the draft exists on firebase
5. Make a note and submit it a. Make sure the note appears on the page. b. Check that firebase has a note, too.
6. Delete the note

Some things that should get broken out separately:

• [x] Verify that Delete Draft resets the form properly.
• [x] Make sure that default list handling is as expected a. The default list should be used if a note is drafted without adding a list. Applies to draft and saved note. b. The last-used list should be used if a note has been previously submitted and no list is added by the user. c. The list added by the user is used otherwise. d. The last-used list updates whenever a note is submitted.

[mmcknett]

Opened #44 and #45 to handle the things that should be broken out separately