🖼️ Images in the header too!

Now finally images are shown in the header too, when logged in or for shared links! :) Icons got a bit more opacity and a shadow to be visible even when backgrounds are light.

Additionally, you can now enable the app only for specific groups. This can be done in the app management. Of course on the log in screen it will always be enabled since it’s not tied to a user.

Contributions are always welcome – join and maybe look through the issue list to see what needs fixing. :)