[FR]: Implement IPC Connection (Linux/macOS)

[FelixSiegel]

It's required to create an inter-process communication (IPC) mechanism that works on both Linux/macOS and Windows platforms, as the Discord Rich Presence relies on this.

The first step, and goal of this feature request, is to implement the linux/macOS part. To achieve this, Unix somain sockets are commonly used.

For more informations about Unix domain sockets and how to implement them, see the following sources:

• Wikipedia: Unix Domain Socket
• Discord RPC Implementation (C++) - Source code of the official Discord RPC implementation
• Discord's Hard Mode Documentation - The only official note from Discord I've found, providing some instructions about implementing your own wrapper of Discord RPC. However, but it's actually more informative to look in the source code of their implementation)

[FelixSiegel]

Decided to write this libary as a python extension module, for easier system related work (unix domain sockets) and more efficiency (even if not really required, as it is just sending & recieving small bytes containing text to the discord ipc interface)