NAS server integration

Instead of having a standalone PHP script for NAS server functionality, this puts the NAS server logic in Python with the rest of the servers. This allows us to make a smaller challenge key (fixing a crash with the gamestats server in Metroid Prime Hunters) and remove some dependencies.

NOTE: By default it binds to the loopback address on port 9000 because binding to low ports on Linux requires root, plus there will probably be a web server bound to port 80. In Apache/Nginx you can proxy connections to the server through http://localhost:9000/