Track serviceworker issues to resolve #4458

[FinnStutzenstein]

The angular issue for this: angular/angular#20970
PR (currently work-in-progress): angular/angular#21842

If this is upstream and released, we can revert the changes in #4458 and use the registerImmediately strategy to load the SW.

[tsiegleauq]

Thanks.
However, that might not be the only thing. We already tried to remove all setInterval and setTimeout from OpenSlides without ever reaching a stable ApplicationRef state

[FinnStutzenstein]

see comment in #4458 : It may not be our mistake, becuase interval and setInterval are not used much and setTimeout should not be a problem..

[tsiegleauq]

Was basically resolved in #4462
Since upstream stuff might change, I leave that open nevertheless. Perhaps we can clean up the app component after this was resolved upstream

[FinnStutzenstein]

I guess we have not to change anything, even if the upstream gets more features. So I'll close this issue.