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.

This seperates the git refs from the rest of the vars because the git refs should end up in
the ami document in mongo but the other vars should not.

also adds some clarifying comments