Write a quick-start guide

[ceski-1]

To help new users.

Cover each major platform:

1. Windows
2. Linux
   a. Packages provided by popular distros (usually very out of date)
   b. AppImage (libfuse, chmod +x)
3. Steam Deck
   a. Gaming mode interface
   b. Desktop mode (Valve's custom Arch Linux distro)
4. macOS

For each platform:

1. How to install Woof
2. How to use soundfonts (FluidSynth, VirtualMidiSynth, etc.)
3. How to set environment variables (DOOMWADDIR, DOOMWADPATH)

[fabiangreffrath]

Should this be one or more Wiki articles or should we extend the information in the README.md document?

[ceski-1]

I think wiki article with sections is good, with a link to it in the README.md.