refactor: remove frontend, move JSONs to json/ top-level

- Archive frontend to community-scripts/ProxmoxVE-Frontend-Archive
- Move frontend/public/json/ -> json/
- Update workflow paths in 5 actions:
  - update-versions-github.yml
  - update-json-date.yml
  - push-json-to-pocketbase.yml
  - delete-pocketbase-entry-on-removal.yml
  - autolabeler.yml
- Remove frontend-cicd.yml (no longer needed)
- Clean up .gitignore (remove frontend-specific entries)

json/netdata.json

@@ -0,0 +1,40 @@
+{
+  "name": "PVE Netdata",
+  "slug": "netdata",
+  "categories": [
+    1
+  ],
+  "date_created": "2024-04-29",
+  "type": "addon",
+  "updateable": false,
+  "privileged": false,
+  "interface_port": 19999,
+  "documentation": "https://learn.netdata.cloud/",
+  "website": "https://www.netdata.cloud/",
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/netdata.webp",
+  "config_path": "/etc/netdata/netdata.conf",
+  "description": "Netdata is an open-source, real-time performance monitoring tool designed to provide insights into the performance and health of systems and applications. It is often used by system administrators, DevOps professionals, and developers to monitor and troubleshoot issues on servers and other devices.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "tools/addon/netdata.sh",
+      "resources": {
+        "cpu": null,
+        "ram": null,
+        "hdd": null,
+        "os": null,
+        "version": null
+      }
+    }
+  ],
+  "default_credentials": {
+    "username": null,
+    "password": null
+  },
+  "notes": [
+    {
+      "text": "Execute within the Proxmox shell",
+      "type": "info"
+    }
+  ]
+}