Fixes #1280

This PR adds a checkbox for admins and super admins to check to confirm whether the transparency report has been received. And integrates with the organizer reminder plugin, allowing users to set how many days after a camp ends a reminder email should be sent if the report has not been received.

How to test the changes in this Pull Request:

1. Add 3 new Automated Reminders.
   • Content: random.
   • Who should this e-mail be sent to? The organizing team (typically city@wordcamp.org) & The Budget Wrangler.
   • When should this e-mail be sent? after the camp ends and no transparency report is received: 7 days & 14 days & 21 days.
2. Create two WordCamps (A reminder must be added before adding a wordcamp; otherwise, the reminder will not be triggered.)
   • You don't need to fill out all the information, just remember to fill in the start date, end date, and the Budget Wrangler's email address; these can be entered arbitrarily. Also, fill in the URL and check the create a new site checkbox. Then Publish.
   • Check if there's a Transparency Report Received checkbox at the bottom of the WordCamp Information section.
     • Switch to different user roles and check if only super admin and an admin+wordcamp author can see the checkbox. (ie. make sure a wordcamp author can't see the checkbox)
3. After WordCamps are created, change their status from Need Vetting to In Pre-Planning.
4. In your first WordCamp, make sure the End Date is NOT set to 7 days ago. Then, run wp cron event run wcor_send_timed_emails --url=https://central.wordcamp.test/ in your docker container.
   • Remember not to set the End Date of the second WordCamp for 7, 14, or 21 days; leave it for future testing.
5. Shouldn't see any email sent on http://localhost:1080/.
6. Set the End Date to 7 days ago and run wp cron event run wcor_send_timed_emails --url=https://central.wordcamp.test/ again.
7. Should see an email with the title and content you set in the reminder sent.
8. Set the End Date to 14 days and 21 days ago respectively and run wp cron event run wcor_send_timed_emails --url=https://central.wordcamp.test/ again.
9. Should see two emails with the title and content you set in the reminder sent.
10. Now let's test the second case, which is when the organizer submits the transparency report, and then the super admin checks off the transparency report.
11. In your second WordCamp, set the End Date to 7 days ago. Then, run wp cron event run wcor_send_timed_emails --url=https://central.wordcamp.test/ in your docker container.
12. Should see an email with the title and content you set in the reminder sent.
13. In your second WordCamp, check off the Transparency Report Received checkbox and set the End Date to 14 days ago. Run wp cron event run wcor_send_timed_emails --url=https://central.wordcamp.test/
14. Shouldn't see any email sent.

Screenshots

Organizer Reminder

Three emails received

Transparency Report Received Checkbox

Four emails received