zuul user

Install a user ``zuul`` that has the per-project key from
``system-config`` as an ``authorized_key``.

**Role Variables**

.. zuul:rolevar:: zuul_user_enable_sudo
   :default: False

   Enable passwordless ``sudo`` access for the zuul user.

.. zuul:rolevar:: zuul_user_authorized_key
   :default: per-project key from system-config

   Authorized key content for the zuul user.