Removing similar lines, updating mask

use  COMMON_PYPI_MIRROR_URL

Added pyexpat to whitelisted shared objects, and flipped apparmor mode to enforce.

Add npm mirror URL

check if variables are defined using proper ansible syntax

Allow to set a custom npm local mirror (e.g sinopia).

use  COMMON_PYPI_MIRROR_URL

Feanil/abbey volume size

Feanil/import xml courses

Jenkins should save the state of the rbenv

Update mysql-python to 1.2.5 for jenkins_worker

Require versions for the course repo checkouts so we can match the versions in
production.

Update import script to spit out yaml configuration and XML mappings for mixed
module store.

Jarv/santize split

creating separate options to clean the prod_grader and wwc dbs