5c661b888e
This change adds support for configuration of Apt package manager in /etc/apt/apt.conf.d/. This allows adding arbitrary global configuration options for Apt. Options can be added in different files, allowing for different filename-based priorities. CI tests and documentation are provided. Story: 2009655 Task: 43987 Change-Id: I9d7d18851359e97cd01b4c2287bf79110796b25a