mod_s2s: Use module API to fire events
These direct accesses are probably more optimized, but weird when the
module API has methods for these things.
For full information on our dependencies, version requirements, and
where to find them, see https://prosody.im/doc/depends
If you have luarocks available on your platform, install the following:
- luaexpat
- luasocket
- luafilesystem
- luasec