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/host-backup.json

@@ -0,0 +1,44 @@
+{
+  "name": "PVE Host Backup",
+  "slug": "host-backup",
+  "categories": [
+    1
+  ],
+  "date_created": "2024-04-29",
+  "type": "pve",
+  "updateable": false,
+  "privileged": false,
+  "interface_port": null,
+  "documentation": null,
+  "website": null,
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/proxmox.webp",
+  "config_path": "",
+  "description": "This script serves as a versatile backup utility, enabling users to specify both the backup path and the directory they want to work in. This flexibility empowers users to select the specific files and directories they wish to back up, making it compatible with a wide range of hosts, not limited to Proxmox.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "tools/pve/host-backup.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"
+    },
+    {
+      "text": "A backup is rendered ineffective when it remains stored on the host",
+      "type": "info"
+    }
+  ]
+}