Docs: Move all docs to a `docs` folder.

This moves all of the documentation into a separate folder, which keeps
everything in one place and avoids unnecessary clutter.

This will pay off when proper guides are written for various aspects of
using awesome or contributing to it.

This also updates the building system, so that the docs are properly
generated with new directories.

Signed-off-by: Ignas Anikevicius (gns_ank) <anikevicius@gmail.com>