feat(configurations)!: flatten down, introduce meta.nix

Flatten down directory structure:
- From: `./hosts/${configuration-type}/${system}/{configuration,deploy}.nix`
-   To: `./hosts/${configuration-type}/{meta,configuration}.nix`
Keep `system` and `deploy-rs` config in `meta.nix`
Update `flake.lock`

hosts/nixos/jeeves/home-assistant/jokes.nix

@@ -0,0 +1,27 @@
+{
+  services.home-assistant.config = {
+    conversation.intents = {
+      TellJoke = [
+        "Tell [me] (a joke|something funny|a dad joke)"
+      ];
+    };
+    sensor = [
+      {
+        name = "random_joke";
+        platform = "rest";
+        json_attributes = "joke";
+        resource = "https://icanhazdadjoke.com/";
+        scan_interval = "3600";
+        headers.Accept = "application/json";
+      }
+    ];
+
+    intent_script.TellJoke = {
+      speech.text = ''{{ state_attr("sensor.random_joke", "joke") }}'';
+      action = {
+        service = "homeassistant.update_entity";
+        entity_id = "sensor.random_joke";
+      };
+    };
+  };
+}