also switch to guavas base64 parser to avoid potential ROM bugs

fixes #3682

RIP symmetry :-(

fixes #3683

turns out libwebrtc doesn’t use the system root CA store but comes with only a few default CAs.

in anyway we will probably only use tcp/443 to bypass firewalls and not to actually secure anything.

That commit never worked because there were other checks in place later down the stream.

Allowing other clients (resources) to correct messages introduces the potential for nasty race conditions.
Furthermore we also have a check in place that would check that the OMEMO fingerprint is the same for security reasons. Removing that check is currently undesirable. Therefor correcting a message from another client would only work for plain text messages (and maybe PGP); this only adds confusion for users for very little benefit.

* Update repo link

* Here too

this will make re-init work if for example retry end card had been reached and we get another call