add Kicksecure APT repository

Hello, I am a Kicksecure and Whonix contributor. Kicksecure and Whonix are developed by the same entity but use different repositories for organization purposes as they are two different projects. You can check the history https://www.kicksecure.com/wiki/History#Relationship_between_Kicksecure_.E2.84.A2_and_Whonix_.E2.84.A2

The targeted repository is https://deb.kicksecure.com

The signing key can be found on: https://www.kicksecure.com/keys/derivative.asc

Same key available on https://salsa.debian.org/extrepo-team/extrepo-data/-/blob/master/repos/debian/whonix.yaml#L25.

Merge request will follow after approval.