upgrade minos scripts to boto3

Wire the ACE_CHANNEL_SAILTHRU_API_* to edxapp

We should be continue using the role-specific variable here to allow
for JWTs signed by ecomworker.

LEARNER-2235

Produce a devstack forums env file

mroytman/fix duplicate image output bug and incorrect image identification bug

This fixes the bug in the _get_role_name method; Travis's environment is at "/home/travis/build/edx/configuration/...", so identifying the Docker image/play name by grabbing the next token after the first instance of the word "build" is incorrect, as it resolves to "edx", instead of the name of the Docker image. Instead, we look for the first token after "docker/build". This also address the duplicate output bug, where, if docker_plays and modified_docker_files have images in common, they would be printed twice.

Ziafazal/yonk 695

Fixed SSO for sandboxes

LEARNER-2107

Add a CONTRIBUTING.md

sandbox.sh will use command-line args for the big playbook run

ENT-464 Defining ENTERPRISE_ENROLLMENT_API_URL

Now that we are accessing this variable in the context of a celery worker,
we noticed that this variable wasn't defined in all of the necessary spots.

Remove redundant apt-get update

password min and max length constraints added 

LEARNER-1492

Ignore logfiles that end in digits by default.

ENT-572: Create permutation configuration file

add modified dockerfiles to the list of plays

jdmulloy/ops1849/remove 12.04