component AP: convert AP identity data to XMPP: metadata are converted to vCard4 (XEP-0292). Avatar is converted to User Avatar (XEP-0084), it is downloaded, resized, converted and cached on first request. If avatar is bigger than 5 Mio, it won't be used. rel 368

these certificates are used for demo purpose only. Those must be the same as in
backend_e2e (they are generated there)