Reorganize modules

hosts/gandalf/mtp-fix.nix

@@ -0,0 +1,30 @@
+{ pkgs, ... }:
+
+{
+  nixpkgs.overlays = [
+    (
+      final: prev:
+        let
+          targetVersion = "1.1.23";
+        in
+        {
+          libmtp =
+            if builtins.compareVersions prev.libmtp.version targetVersion >= 0 then
+              prev.libmtp
+            else
+              prev.libmtp.overrideAttrs (_: {
+                version = targetVersion;
+
+                src = final.fetchFromGitHub {
+                  owner = "libmtp";
+                  repo = "libmtp";
+                  rev = "v${targetVersion}";
+                  hash = "sha256-FlPj9PEeOAWabU11dFTzDgY9TBbgmJclbeL0iULYw6A=";
+                };
+
+                patches = [ ];
+              });
+        }
+    )
+  ];
+}