Add 'welcome banner' extension API (#3656)

* Add react-material-ui-carousel

Signed-off-by: Hung-Han (Henry) Chen <chenhungh@gmail.com>

* Add welcomeBanners extension api

Signed-off-by: Hung-Han (Henry) Chen <chenhungh@gmail.com>

package.json

@@ -230,6 +230,7 @@
     "proper-lockfile": "^4.1.2",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
+    "react-material-ui-carousel": "^2.3.1",
     "react-monaco-editor": "^0.44.0",
     "react-router": "^5.2.0",
     "react-virtualized-auto-sizer": "^1.0.6",