Revert "validate certs=no on apt_repository due to ansible bug"
Merge pull request #1642 from edx/revert-1641-derf/validate_certs_no

Revert "validate certs=no on apt_repository due to ansible bug"
Switch from legacy variable templating system to Jinja2 everywhere
Add spacing to match coding conventions.
Add back dollarsigns to the vars that need it.
Remove last known dollar vars.
Upgrade ansible and its dependencies.
Fix spacing to deal with a bug introduced in ansible 1.7.2
Fix spacing in other roles.
Update default for 3rd party auth to an empty dict.
Revert to ansible 1.6.8 due to a template bug.

See https://github.com/ansible/ansible/issues/9362
Move ansible back for now.
Use $ for EDXAPP mongo port.
Put back the other $ vars.
Disable old ORA on sandboxes by default.