Jarv/gather assets fix

Introduce POST size limit for ORA submissions

This was causing problems when gather_assets ran

The ORA machinery gets gummed up when it gets very large submissions and
throws a lot of 500s.

Co-Authored-By: Jason Bau <jbau@stanford.edu>

removing start secs for certs

changing reload to a notify

Move ora to supervisor

Some environment changes to speed up deploys

This is so that we can have multiple supervisors running
in different virtual envs

adding another push queue

* Instead of using pypi.edx.org why not cache on localhost?
  Seems to work well and it does result in a speed improvement
  for when we need to download packages. This adds the devpi
  role as dependency for edxapp
* For edxapp we md5sum all fo the requirements files and only
  run the pip installs, bundle, npm tasks if any one of those
  files have changed (it treats them as a group)
* Adds convenience symlinks for pip

Use the EDXAPP_LANG var which already exists.

Add github.com to ssh known_hosts for jenkins

fixing check for cluster config

Change the default cloudformation elb backend ports.

mongo_clustered defaults to !!null

Now they default to the same as what is set in ansible which should reduce the number of things
we have to override when running ansible on a VPC.

Update to use cluster enabling vars in both rabbit and mongo.