Add time_offset to support local timezone

meshtastic/config.proto

@@ -180,6 +180,11 @@ message Config {
      * Disables the triple-press of user button to enable or disable GPS
      */
     bool disable_triple_click = 10;
+
+    /*
+     * Timezone offset against UTC in minutes, to support the few places with fractional offsets.
+     */
+    int32 time_offset = 11;
   }
 
   /*