✨(service-worker) add service worker api to impress app

This commit adds the service worker api to the
impress app.
The service worker api will cache the api calls
in the indexdb. We are using the network first
strategy to fetch the data. If the network is
not available, we will fetch the data from the
indexdb.
To do that, we create a custom plugin (ApiPlugin).

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to
 - (frontend) manage members (update role / list / remove) (#81)
 - ✨(frontend) offline mode (#88)
 - (frontend) translate cgu (#83)
+- ✨(service-worker) offline doc management (#94)
 
 ## Changed