If our alias matches the contact's nickname, it seems like Briar only
exposes the author's nickname and leaves out the alias field.

Also refactor socket_listener.py to make it more general.

With links back to base projects.

Also split up login and registration.

https://gitlab.gnome.org/World/podcasts/blob/bcd610e2e377d70ff75f52bbfae4d2007a248a90/CONTRIBUTING.md
https://gitlab.gnome.org/World/podcasts/blob/master/code-of-conduct.md

briar@9ebe49b8

It complains about duplicate import lines and I don't want to abstract
them now.

For this to work, you have to put this project (GTK) and Android's
project into one directory and call the Android's folder
"briar-android".