db connection with auth config leads to error in webapp

see #18 - running the webapp from the plugin with a db connection that uses qgis auth configuration leads to an error:

Fehler beim Starten der Webapp: (psycopg.OperationalError) connection failed: connection to server at "10.200.160.198", port 5434 failed: fe_sendauth: no password supplied
(Background on this error at: https://sqlalche.me/e/20/e3q8)

credential transfer has to be adjusted.