Support non-strict mode for repeater

This commit makes possible:

* Starting repeater without VPN;
* Repeater will work better with stub VPN apps;
* LAN addresses will be reachable.

mobile/src/main/res/xml/pref_settings.xml

@@ -8,6 +8,10 @@
             android:summary="%s"
             android:singleLine="true"
             android:defaultValue="8.8.8.8"/>
+        <SwitchPreference
+            android:key="service.repeater.strict"
+            android:title="@string/settings_service_repeater_strict"
+            android:summary="@string/settings_service_repeater_strict_summary"/>
         <Preference
             android:key="service.clean"
             android:title="@string/settings_service_clean"/>