hosts: rearrange modules a bit

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

hosts/nix.nix

@@ -0,0 +1,29 @@
+{ config, pkgs, ... }:
+{
+  nixpkgs = {
+    config = {
+      allowUnfree = true;
+      allowBroken = true;
+      allowInsecure = true;
+    };
+  };
+
+  nix = {
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+    settings = {
+      auto-optimise-store = true;
+      trusted-users = [ "root" "natto" ];
+      substituters = [
+        "https://nix-gaming.cachix.org"
+        "https://nix-community.cachix.org"
+        #       "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store"
+      ];
+      trusted-public-keys = [
+        "nix-gaming.cachix.org-1:nbjlureqMbRAxR1gJ/f3hxemL9svXaZF/Ees8vCUUs4="
+        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      ];
+    };
+  };
+}