Major improvement to dome9 role structure.

Notable changes:
Addition of idepotency by adding a touched file assessing an already
pair machine.
Addition of variable to enable and disable role.

Addition of dome9.yml tasks file so that the main.yml file and
reference the dome9 file if enabled. This also allows me to tag the
role by default.
New main.yml file.

This file will include dome9 tasks to run if the role is enabled. This
also allows for a default tag to reference for the dome9 role.