Send daily leaderboard notifications at chosen timezone

[Kevin-Roman]

Description

This feature was previously intentionally decided not to be implemented due to implementation difficulties in relation to the database design 0122511.

However, with the May 2024 database redesign, I don't believe the limitations still apply, making this feature feasible. However, this would entail needing to store users' data at every interval (30 minutes) rather than daily, vastly increasing the amount of user data stored. Any such changes would require checking if they affect other systems, such as the leaderboards and general notifications.

Implementation of this feature would likely entail:

1. Storing the chosen timezone for each server.
2. Providing a user-facing option/command for changing the timezone.
3. Storing user records every scheduled update (30 minutes), or taking a shortcut / making assumptions which would not work for edge cases (switching between timezones).
4. Updating the notification and leaderboards systems which use Records, to make sure they retrieve the correct info at the appropriate times rather than assuming midnight UTC.
5. Updating the daily leaderboard notification logic to take into account the chosen timezone.
6. Validating the systems work as intended with no side effects.