Added option to specify migration user and changed to admin user and password vars
Changes to unify edxapp and worker AMIs.

Always write the supervisor files and link them as necessary.

Drop the configs in the supervisor available directory. Instead of having a
seperate cfg dir for each service.

Seperate devstack logic from disabling supervisor tasks. Add the new flag so
devstack continues to not startup supervisor. Use new supervisor_available_dir
everywhere.

Remove mongo logic from abbey and remove stage_release. This should completely
remove our tie ins to mongo.

Also removing monitor repos script which depended on stage_release. We can add
in similar logic when we're ready to automate building the AMIs on rc branch
creation.

Updated requirements.
Do this as the supervisor_user since the services user won't be able to write to the cfg dir.
Update the build-ami jenkins job.
Remove prepare jobs.
Update jenkins_admin xml.
Ensure we have the right version of pip.
Move templates to better show where they'll endup.
One when instead of two.
commoncluster play
fixing path in comment
Merge pull request #892 from edx/e0d/commoncluster-play

commoncluster play
Merge pull request #888 from edx/feanil/disable_supervisor_runs

Feanil/disable supervisor runs
Template not file.
Merge pull request #893 from edx/feanil/damn_copy_paste

Template not file.
Fix devstack and CI breakage.
Pin devstack to the release branch of configuration.
ensure python-mysqldb is installed before we attempt to create_dbs
Add missing variable MKTG_URLS in configuration
Merge pull request #900 from ionis-education-group/mktg-urls-missing

Add missing variable MKTG_URLS in configuration