thank you for your interest in packaging for the Univention App Center!
Yes, the package needs to be installed unattended. This can be "simulated" by doing:
apt-get -y --force-yes -o DPkg::Options::=--force-confold install my_package
This is more or less what the App Center will do. Have you tried specifying defaults for dbconfig and then just run this command? people.debian.org/~seanius/polic ... s-defaults
You need to provide an .ini file, a .png logo, and maybe a screenshot and some README files. These files are not part of any package, but meta information that you need to send separately to Univention. We will take care of putting it in the right place so that users can "access" those files prior to installing the application.
See docs.univention.de/developer-ref ... app:upload for the uploading process.