Add server time zone

Add an admin/mod command to where they can set server's local time zone.
Then the time displayed in that server should be in that time zone.
One can look at the latest commits of https://github.com/aryanc403/TLE/tree/localtime to see more details about this.

Start by reviewing the latest commits on the linked localtime branch and trace the existing admin/mod command handling and time-display entry points in TLE. Identify how a server time zone should be stored and applied, then verify that authorized users can set it and displayed times use that server's setting.

Written by the indexing model from the issue text.