Merge pull request #1034 from edx/jarv/clean-ami

Jarv/clean ami
Preview module store.
Adding mapping for preview host.
Removing preview hash gen.
removing preview runtime config.
Deleting legacy templates.
removing unused config.
should be a dict.
Merge pull request #1040 from edx/e0d/preview

E0d/preview
Remove the repo.txt requirements file.
Merge pull request #1125 from edx/feanil/repo_req_release

Feanil/repo req release
updated edxapp ansible role to include the ability to enable third party authorization
Play to create the analytics db and users
using pip to install mysql lib
Made more generic
Upgrade `requests` module to 2.3.0
Upgrade `oauthlib` module to 0.6.3
renaming to be more generic
Updates to apache role to make it more flexible and inline with nginx
Old style role pipe missed