feat(schedules): add timezone support for scheduled jobs and update database schema

- Introduced a new `commonTimezones` array for timezone selection in the UI.
- Updated the schedule form to include an optional timezone field.
- Modified the database schema to add a `timezone` column to the `schedule` table.
- Enhanced the scheduling logic to utilize the specified timezone, defaulting to UTC if not provided.

apps/dokploy/server/utils/backup.ts

@@ -19,6 +19,7 @@ type QueueJob =
 			type: "schedule";
 			cronSchedule: string;
 			scheduleId: string;
+			timezone?: string | null;
 	  }
 	| {
 			type: "volume-backup";