core: Add AppArmor profile switching

This permit to switch to a specific apparmor profile when starting a daemon. This
will result in a non operation if apparmor is disabled.
It also add a new build requirement on libapparmor for using this feature.
replace tabs with spaces in some files

Files:
* hwdb/60-keyboard.hwdb
* shell-completion/zsh/_systemd-coredumpctl
* src/test/test-helper.h