Jbau/fix/xqueue underscore

it was not called for

Initial set of files to bring up a staging edx

The main thing of interest here is stage-ansible.cfg and
stage-ssh-config, which taken together offer a way to have an
environment with different access control policies and a different VPC
jumpbox without disturbing the usual case of working with your VPC
production hosts.

To run this, edit stage-ssh-config with a sensible jumpbox configuration
and make sure the options in stage-ansible.cfg are the set of ansible
options you expect to use, then invoke ansible with ANSIBLE_CONFIG like
so:
```
ANSIBLE_CONFIG=stage-ansible.cfg ansible-playbook -v -i './ec2.py' edxapp_stage.yml
```

Add lynx to packages for converting html to plaintext

use edxapp instead of individual gunicorn processes

Conflicts:
	playbooks/edx-west/edxapp_prod.yml

Feanil/ansible xserver

  - For multipart email

Allow for the app armor configuration files to be loaded from secure repo if
available and loaded from the base configuration otherwise.

Update git source repos to https

* Now that edx-platform is fully open source, the right thing to do is
  have read-only http URLs be the default and get rid of all the
  nonsense ssh-oriented infrastructure for config/deployment.
* This patch makes all the git repository references use the read-only
  https urls and removes the git_ssh and 'deployment' ssh key kludges.
* Also contains updates to edx-west/edxapp_prod.yml which make its
  behavior less mysterious. (but this isn't the important part)

Jarv/xqueue support