Feanil/retire xenial hosts

Syslog creates it lazily which causes s3 log syncing to break if this doesn't already exist.

systemd.

- Systemctl doesn't have a no-wait parameter.
- Shell instead of command to send logs to s3, command was failing on
  '||'

Updating all AMI, including the edx install

These are expanded in common.py, but too late

We have to use the full name when overriding.

Bump agent versions

Note that their URLs changed so I had to tweak the data structure.

Ensure this is available in lms.env to be overridden.

Feanil/test sandbox build

Jibsheet/programs on 16.04

Update common to pull down the non-ppa python on 16.04

(cherry picked from commit dd3c15bf019c6538ed8b83834fd2dc5b1a51a1db)

Instead of making the change just for ansible-provision.sh make the
change for all ansible runs.  Most of them don't currently have this
problem right now but I think it makes sense to make them all consistent
and not have to worry about this problem in the future.

When ansible is going over a NAT Gateway or other intermdiate
network devices, the connection can time out if that device has
its own timeout setting for no traffic.  Setting the ServerAliveInterval
will ensure that there is data sent over the wire ever 30 seconds so the
connection does not get closed while running ansible tasks that take
over 5 minutes.

update packer scripts to use ansible bootstrap script

These defaults are conflicting with the overrides.

ECOM-6238

Max/update pipeline migrations

Simplify the data table we need to change with each release

Jibsheet/use configuration source checking

Simple playbook to take security updates on hosts

add security upgrade flag to te jenkins plays