Resolve "Hiden anonymous login"

Closes #57 (closed)

When opening the app, it will immediately log you in as anonymous in the background. You will then be prompted to log in if you want to see private data in a popup, which you can ignore if you want, by closing it.

If you choose to ignore it, the anonymous login will then be used and you can browse the app (you see yourself as not logged in, with option to log-in highlighted in the top right):

No changes compared to previous version when actual user is logged in.