Privacy Issue: Remove request to any third-party

[jankapunkt]

Summary

When watching the network activity of openqda there is still a request to https://ui-avatars.com/api which we need to get rid of as this is a privacy concern.

Reproduction

If you have registered but no profile image uploaded, then go to any working page (preparation, analysis etc.) and watch the Network tab in browser dev tools.

A request to https://ui-avatars.com/api is shown in the list.

Expected behaviour

No requests to any server outside of our ecosystem (Core, Plugins etc.)

We also have to make sure there are no requests to any other third party, not detected yet (for example google fonts, CDNs etc.)

[alessandrobelli]

Ui avatars is an open-source website that, at least, claims that it is not storing any data.

If we are legally required to don't send any request outside Bremen or Germany, we can remove it in 5 minutes, but we need an alternative to the avatar placeholder.