Fetch pkg/lib automatically from cockpit instead of keeping a local copy

* remove mustache module as it's not used anymore.
* port alert component to react-core as the current code creates a
broken UI

package.json

@@ -51,10 +51,10 @@
     "@patternfly/react-table": "^4.8.6",
     "comment-json": "^1.1.3",
     "core-js": "3.6.5",
+    "date-fns": "2.25.0",
     "ini": "^1.3.5",
     "jquery": "3.5.1",
     "moment": "2.27.0",
-    "mustache": "2.3.0",
     "raw-loader": "^0.5.1",
     "react": "16.13.1",
     "react-dom": "16.13.1",