squash! Move device-specific config to a separate module

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/b1957596ff1c7aa8c55c4512b7ad1c9672502e8e' (2022-06-15)
  → 'github:NixOS/nixpkgs/3d7435c638baffaa826b85459df0fff47f12317d' (2022-06-16)

flake.lock

@@ -38,11 +38,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1655306633,
-        "narHash": "sha256-nv4FfWWV/dEelByjXJtJkoDPOHIsKfLq50RN3Hqq5Yk=",
+        "lastModified": 1655400192,
+        "narHash": "sha256-49OBVVRgb9H/PSmNT9W61+NRdDbuSJVuDDflwXlaUKU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "b1957596ff1c7aa8c55c4512b7ad1c9672502e8e",
+        "rev": "3d7435c638baffaa826b85459df0fff47f12317d",
         "type": "github"
       },
       "original": {