Allow changing timezone of the schedule display in tournament client

[Zyfarok]

Describe the new feature: Allow to choose the timezone in which the match times are displayed in the osu!lazer tournament client Schedule page. As I'm hosting a french tournament, having times displayed in UTC feels strange when all players are in the CET/CEST timezones (UTC+1 in winter, UTC+2 in summer).

Proposal designs of the feature:

• Have an option to choose the timezone in the Setup page. I see three ways of doing it:
  • just having a place to set up the offset with UTC, but then you might want to add an input field for the DST (daylight saving time) offset too.
  • An other simpler way could be to have a tick box to use the streamer's PC local time... but that could "break" on DST changes if not not done properly.
  • Just have all world timezones (based on cities like on linux/windows) in a dropdown menu.
• Display the schedule in the set-up timezone
• Allow to write times in local-time in the bracket editor ? Making an error when setting up is easy when your tournament spreadsheet is in local-time

[peppy]

Would be great to have this if someone finds the time to implement as a setting. Might even be enough to read current culture for DrawableDate. And add a checkbox in tounament client to force to UTC.