update the apt submodule in order to get the fix for unattended_upgrades (#2984) and the custom_key_dir as a class parameter

remove the global variable from setup.pp and site.pp and instead pass it into the apt class declaration as a parameter

Change-Id: I24806f2fd22b5a066b951c5f76f3dd748481b5b6
Merge branch 'bug/2984' into develop
Merge branch 'develop' into leap