Configure NLTK_DATA environment variable for ORA celery workers

This converts lms-preview variant to supervisor

and adds a clause to rake not to gather assets as it fails

Checkout ease and ora master branch instead of HEAD

Disable basic auth for 127.0.0.1

Replace ORA XQueue vars

Add notifier configuration options

This change corresponds to notifier commits 73c67a9 and 88aa593.

Fix typo in default 'from' email

Set default emails.

Remove MITX from the name of the features dict.

This is to correspond to the same fix in the edx platform.
https://github.com/edx/edx-platform/pull/1827

Without this, the defaults get set to '' and then sentences on the site look weird because the emails are missing.

add readme file for edx-west, prod-log playbook (into master)

using role dependencies for common/supervisor

adding vars_files for nginx

fixing nginx_sites for provisioning

While in here do a couple of cleanups:

- remove a log file
- add a simple playbook for refreshing roles on the prod log machine

adding option to enable basic auth when we provision

Make basic_auth a global nginx parameter

Instead of enabling basic auth per role this makes it
an nginx parameter which makes more sense for sandboxes
and probably other servers where we want basic auth turned on

removing basic auth credentials.

Feanil/stage