It's handy to be able to create users that *don't* have sudo rights.
Here at Stanford we use this to add users to our VPC bastion box (ssh
proxy) so these users can use this machine for ssh tunneling, but I
don't want to give those users the keys to the kingdom.

This let's me configure a playbook like this.

   roles:
     - common
     - supervisor
     - role: gh_users
       gh_users:
         - su1
         - su2
         - su3
       gh_users_no_sudo:
         - normal1
         - normal2

The new gh_users_no_sudo list can be empty.

E0d/commoncluster

change to chmod as privileged user.

adding EDXAPP_LOCAL_GIT_IDENTITY to abbey.py

also adds some clarifying comments

E0d/es cluster

edxapp-git-auth: allow authenticated edx-platform/edx-theme checkouts

Using `EDXAPP_LOCAL_GIT_IDENTITY` gives parsing errors during evaluation for paths

Setting default username to root and defalut db name to edxapp.

Change how abby gets notified.

We were previously using the jenkins api which was more complicated than the
buildByTokens plugin and its API.

Jarv/focaccia

Feanil/mckinsey abbey

These vars are also set by the jenkins job