This commit is a dirty hack to fix issue with ARM64 Prosody AppImage.
The fixed appimagebuild tool is not released by the dev team.
So i patch it in my build script. This is not a good solution, but it
works, and let me go forward.
Note: websocket s2s is not working yet, still WIP.
New Features
* Chat Federation:
* You can now connect to a remote chat with your local account.
* This remote connection is done using a custom implementation of [XEP-0468: WebSocket S2S](https://xmpp.org/extensions/xep-0468.html), using some specific discovering method (so that it will work without any DNS configuration).
Minor changes and fixes
* Possibility to debug Prosody in development environments.
* Using process.spawn instead of process.exec to launch Prosody (safer, and more optimal).
* Prosody AppImage: fix path mapping: we only map necessary /etc/ subdir, so that the AppImage can access to /etc/resolv.conf, /etc/hosts, ...
* Prosody AppImage: hidden debug mode to disable lua-unbound, that seems broken in some docker dev environments.
* stop trying to generated an ARM64 AppImage (as it is buggy)
* display a warning in the settings if incompatible CPU detected
* documentation for a workaround
Implements #120.
