Add role to configure APT

Move auto upgrade config from cu-custom role to apt-config

	new file:   roles/apt-config/README.md
	new file:   roles/apt-config/defaults/main.yml
	renamed:    roles/cu-custom/files/20auto-upgrades -> roles/apt-config/files/20auto-upgrades
	new file:   roles/apt-config/meta/main.yml
	new file:   roles/apt-config/tasks/main.yml
	modified:   roles/cu-custom/tasks/main.yml