api/schema: get schema without having a machine

Also done:
- add @pytest.mark.with_core indicating that a test depends on clan-core and cannot be cached
- separate unit tests into two derivations, ones that can be cached and ones that cannot.
- fix frontend typescript code

clanModules/flake-module.nix

@@ -1,13 +1,11 @@
-{ self, lib, ... }: {
+{ inputs, ... }: {
   flake.clanModules = {
-    diskLayouts = lib.mapAttrs'
-      (name: _: lib.nameValuePair (lib.removeSuffix ".nix" name) {
-        imports = [
-          self.inputs.disko.nixosModules.disko
-          ./diskLayouts/${name}
-        ];
-      })
-      (builtins.readDir ./diskLayouts);
+    diskLayouts = {
+      imports = [
+        ./diskLayouts.nix
+        inputs.disko.nixosModules.default
+      ];
+    };
     deltachat = ./deltachat.nix;
     xfce = ./xfce.nix;
   };