✨(frontend) add offline mode support

Add a offline mode support from a service worker.
The service worker will cache the assets and the
visited pages to be able to work offline.
Created a fallback page for when the user is offline
and tries to access a page that is not cached.

src/frontend/apps/impress/.gitignore

@@ -33,3 +33,5 @@ yarn-error.log*
 
 # typescript
 *.tsbuildinfo
+
+service-worker.js