Verify CAP 2 support in Blue Horizon Installer GUI and add to docs

[btat]

Carried over as separate issue from #723 and #724

When you get to this, check to see if the Blue Horizon installer GUI (in the marketplace)
is supporting CAP 2.0. Docs should point to that and the cap-terraform scripts a
 options to a completely manual installation.

[btat]

Marking as blocked. As per Satadru, the terraform scripts themselves have not been updated for 2.0. Once they have, we will be notified and will continue looking into this.