To ensure they are taken into account before we try to start the process
through supervisord.

supervisord as well as all the processes it controls are run as
`{{ common_web_user }}`. This allows us to connect to it as that
user which allows us to manage the processes as www-data, instead
of root.

Since the data is not at a standard location anymore, set the location through
a environment variable, `NLTK_DATA`.

`XQUEUE_BASIC_AUTH` was declared twice for two different usages: activating/deactivating
the auth (boolean), and a [login, password] list. Split the second usage (login/password
list) into two separate variables, like the corresponding django_auth variables.

Source the `activate` file instead of attempting to execute it, which requires
execution rights.

creating syslog writable log dir

always run the create xqueue user task

Update the jenkins worker to use the mongo role.

The common role also has to be included because vars that were previously being set in group_vars_all are now in
the slimmed down common.

Jarv/fix shell commands

adding role for importing the demo course

Certain tasks (like generating grades) require a great deal of

memory that isn't properly freed up. This creates a queue for such
workers so that we can give them different configuration settings
-- in this case, setting CELERYD_MAX_TASKS_PER_CHILD=1 to force
workers to die after they process one job. Because these jobs tend
to run for hours, the overhead is not a big deal.

Common refactor - Applies changes to edx_sandbox

some forum deploy tasks missing the deploy tag

Jarv/common refactor