Check if the pool id have already been attached

Sometime subscription-manager returns an error but have subscribed to
the pool ID. Add a check to ensure that the pool ID have been attached
and not let the subscription task fail.
Merge pull request #29 from elyezer/pool-id-check

Check if the pool id have already been attached
Added task to install/configure from CDN.

We can now install and configure Satellite 6 straight from CDN.
Merge pull request #31 from omaciel/cdn-installer

Added task to install/configure from CDN.