Feature request: Selectable time zone

Would be great if there was a dropdown in the settings to choose an alternate timezone from the default (system time). Personally I keep my system time set to Europe where my son is now, but sometimes I need a clock that shows me local time. Sometimes vice versa.

Start by locating the settings UI and the code that renders the clock, then trace how system time is selected. Define how a user chooses an alternate timezone and switches between it and system time. Done means the selected timezone is available in settings and the displayed clock updates correctly.

Written by the indexing model from the issue text.