cmd/syncthing: Add more stats to usage reports (ref #3628)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4347

cmd/syncthing/mocked_connections_test.go

@@ -11,3 +11,7 @@ type mockedConnections struct{}
 func (m *mockedConnections) Status() map[string]interface{} {
 	return nil
 }
+
+func (m *mockedConnections) NATType() string {
+	return ""
+}