feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.config/karabiner/assets/complex_modifications/1668261369.json

@@ -0,0 +1,31 @@
+{
+  "title": "Caps Lock to Escape, enable Caps Lock when held",
+  "rules": [
+    {
+      "description": "Caps Lock to Escape on single press, Caps Lock on press and hold.",
+      "manipulators": [
+        {
+          "type": "basic",
+          "from": {
+            "key_code": "caps_lock",
+            "modifiers": {
+              "optional": [
+                "any"
+              ]
+            }
+          },
+          "to": [
+            {
+              "key_code": "escape"
+            }
+          ],
+          "to_if_held_down": [
+            {
+              "key_code": "caps_lock"
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}