feat!: dynamically create hosts

This commit completely restructures the flake. Hosts are now seperate
from profile configuration files in hosts/[system]. Nixos and Darwin
configurations will be built when present in the respective folders in hosts/

profiles/server/nixos/packages.nix

@@ -0,0 +1,10 @@
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    gnupg
+    nix-index
+    ssh-to-age
+    git
+    emacs
+  ];
+}