build: add determinate nix support for darwin

- Add determinateSystems/determinate flake input
- Include determinate darwin modules in configuration
- Disable legacy nix module configuration
- Remove modules/darwin/nix/default.nix
- Add mac-va-mbp-work system using determinate nix

systems/aarch64-darwin/mac-va-mbp-personal/default.nix

@@ -1,12 +1,13 @@
 {
   system.stateVersion = 6;
-  nix.enable = false;
+
+  # System Config
+  determinateNix = {
+    enable = true;
+    nixosVmBasedLinuxBuilder.enable = true;
+  };
 
   # System Config
   reichard = {
-    nix = {
-      enable = true;
-      usingDeterminate = true;
-    };
   };
 }