Write manual regression test cases and add to TestRail

[rwood-moz]

In order for our QA partners to run manual tests against TB Appointment we need to write some manual regression test cases and add them to TestRail. A couple of notes:

• The tests should focus on testing TB Appointment on the stage environment and expect any test dependencies to already be setup there
• Include test cases around the new feature of using Google Calendar API for invites (Use Google Calendar API calendar invites / Implement Push Notifications #1529) which is currently behind a feature flag and will need to be tested before turning on the feature for our Appointment users; I will collaborate with @davinotdavid on this
• Focus on creating manual test cases to test flows that are not already covered by our automated E2E tests