Convert to flake-parts & easy-hosts. Users broke

convert to using flake-parts and easy-hosts for the flake system. This
allows me to remove my poor file-system based code and replace it with
the code done in easy-hosts. Which also has good knock-on effects.

This change factors users out of hosts, which is probably a good change
since users aren't a nixos-module, but aren't completely untangled
either.

I'm going to leave users broken for a minute as I decide exactly how I
want to handle them.

.gitignore

@@ -0,0 +1 @@
+result