Page Livecycle API

[ChristianMayer]

We should consider supporting the Page Livecycle API as the CV is a long running application.
-> https://developers.google.com/web/updates/2018/07/page-lifecycle-api

[peuter]

Could be implemented using Qooxdoos FiniteStateMachine (maybe?): http://cometvisu.org/CometVisu/en/latest/api/#qx.util.fsm.FiniteStateMachine

Basically its about resuming the backend-connection (read-request) right? Or are there other things that need to know that state? I guess if not its only relevant for long-polling transport, because the SSE-Connection is handled by the browser anyways.