[OMEMO] Show QR-Code of own fingerprint for easy verification

[cweiske]

The Android Conversations xmpp client allows verification of fingerprints by scanning the QR-code on other devices.

It would be nice if psi's omemo plugin would show the QR code of the own fingerprint.

Screenshot of Dino's QR fingerprint popup:

The contents of the QR code seem to be:

"xmpp:" + jid + "?omemo-sid-" + device-id + "=" + fingerprint

for each additional fingerprint, add::

+ ";omemo-sid" + device-id + "=" + fingerprint

Also: omemo/gajim-omemo#146

[tehnick]

It may be easily implemented using zxing or any other widely used C++ library. But this is one more build dependency...