Add chapter on windowing/audio/input libraries

[SaschaWillems]

During a recent call we talked about libraries to help Vulkan developers with stuff not directly part of the api. This includes the platform specific windowing setup, audio and input.

There are several libraries that offer this:

• SDL
• sfml
• glfw

We have a list of (some) of those at https://vulkan.org/tools but having something with a bit more detail in the guide could also make sense.