WIP: Replace Xabber's untrusted Maven repository for Smack
Xabber was using an untrusted Maven repository for Smack version 4.2.1. I have added a patch to replace this with the latest version from Maven Central, which is 4.2.0.
I have flagged this WIP because i am not sure if this would be an acceptable solution. I have compiled and installed the app and it appears to be working correctly, but i have not tested it extensively.