Data-fetch routine:
fetch room information from server
-> if unsuccessfull load room from disk
The room will automatically be closed,
if either of the following conditions apply:
- the user is offline and no data was found on disk
- the network request returned a server error
and rewrote the component's network requests.
showSimpleSnackbar, allows displaying a simple snackbar,
with text and one action button, that can be clicked.
doNetworkRequest is supposed to be a wrapper for the
already existing post* functions.
It aims to make network requests and error handling easier,
by containing all the try&catch blocks
and being able to show snackbars.
