The CAT-Tool is a directly executable Python-Script with your standard user-privilleges.
In the terminal:
python3 edoroam-linux-Universitat_Konstanz-Uni_Konstanz.py
Confirm the requests and enter, when asked for your username, your full email-adress (firstname.lastname@uni-konstanz.de) and your password.
The configuration assistent will create a configuration file for wpa_supplicant, if the network manager isn't installed. You can use this to connect to eduroam without a network manager. For further information about wpa_supplicant please refer to you distribution's documentation.
If the network manager is installed and you still only get the configuration file for wpa_supplicant, check if the package "python-dbus" or "python3-dbus" is installed. If not, please install it.