When changing the uuid clear the password

Because id is used as part of the encryption process the value is not a valid encoded password anymore.
We could decode en reencode the password but wanted a quickfix for now.
This is also prevents the weird behaviour that it asks for the manager password but then has to prompt for the connection password.

pglab/ConnectionController.cpp

@@ -100,6 +100,7 @@ void ConnectionController::editCopy(QModelIndex index)
     if (config) {
         auto cc = *config;
         cc.setUuid(QUuid::createUuid());
+        cc.setEncodedPassword({}); // maybe we should decode en reencode?
         editConfig(cc);
     }
 }