[WIP] SOC_U: Implemented some socket functions

This allows FTPony to work.
It's using Berkeley sockets directly since that's what the soc:U service exposes to applications.

Still WIP.
This should actually use the provided len instead of sizeof(sockaddr_in), however bind() was returning an error because the provided len is always 8 in my tests, and bind() requires the length to be at least sizeof(sockaddr)