bump various libraries that have been waiting for androidx

Migrate from Android Support Library to AndroidX

Unignored gradle.properties since androidX requires additions there
See also https://developer.android.com/jetpack/androidx/migrate

added XEPs for a/v calls to doap file

pulled translations from transifex

fix in call notification being shown twice

code clean up

pulled translations from transifex

version bump to 2.9.4 + changelog

pulled translations from transifex

just xmpp things

Revert "offline presences aborts session proposals. fixes #3943"

This reverts commit f23016c967c87df28543b781b15780f1f877802e.

add 'id' attribute to outgoing ICE-UDP candidates

this attribute is mandatory as per the XEP.

use libwebrtc-m87

use svg logo in doap file

properly null check ufrag and pwd before whitespace checking. fixes #3956

pulled translations from transifex

version bump to 2.9.3 + changelog

pulled translations from transifex

minor code clean up in XmppConnection class

implement SCRAM-SHA512