[BUG]: socket.io on subfolder Installation not working

[andi34]

Describe the bug

Since the Webserver IP needs the subfolder added (in case) to get the QR Code working, it makes trouble on the remotebuzzer server.

Steps to reproduce the behavior

Make a subfolder Installation of Photobooth
Setup Remotebuzzer
See it failing on the Client, can't connect.

Expected behavior

Connected Client to the remotebuzzer server.

Photobooth Version

Latest dev branch

Browser and browser version

No response

Operating System

Pi OS

Did it work before?

No

Latest working version

Additional context

[andi34]

Once this bug is fixed I'll provide a ne stable release for users. This would also allow installing stable3 via git again on buster based Pi OS