create device descriptions for all

owrx/source/rtl_tcp.py

@@ -1,4 +1,4 @@
-from .connector import ConnectorSource
+from owrx.source.connector import ConnectorSource, ConnectorDeviceDescription
 from owrx.command import Flag, Option, Argument
 
 
@@ -16,3 +16,7 @@ class RtlTcpSource(ConnectorSource):
                 }
             )
         )
+
+
+class RtlTcpDeviceDescription(ConnectorDeviceDescription):
+    pass