Add an Android panel for own and peer DM devices

tools/chatgui-android/app/src/main/res/values/dm_groups.xml

@@ -1,5 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
+    <string name="dm_members_title">Conversation devices</string>
+    <string name="dm_my_devices">My devices</string>
+    <string name="dm_peer_devices">Peer devices</string>
+    <string name="dm_members_unavailable">Could not refresh the device list</string>
     <string name="dm_mode_title">Devices for this conversation</string>
     <string name="dm_mode_groups">With device groups</string>
     <string name="dm_mode_device">Only these devices</string>