This commit contains the following changes:
- nixos/sway: Remove the beta references
- sway: Drop buildDocs
- nixos/sway: Improve the documentation
- sway,nixos/sway: Adapt Sway to NixOS
- Copy the default configuration file to /etc/sway/config (Sway will
still load the identical file from the Nix store but this makes it
easier to copy the default configuration file).
- This will also remove all references to the Nix store from the
default configuration file as they will eventually be garbage
collected which is a problem if the user copies it.
- I've also decided to drop the default wallpaper (alternatively we
could copy it to a fixed location).
- nixos/sway: Drop the package option
