Create version picker dropdown on cluster provisioning page

(edit GS nov-11-2021 – re-purposing this for adding a version selector to the new OSD wizard)

Our API permits selection of version and channel during OSD cluster provisioning.

This card is to create a version picker dropdown to allow any user to pick a version (includes z-streams) to install.

The version picker should be tied into our feature flags, so that if I am logged in as a user who can access non-stable versions, I see those in my options list (same as I would see in output of ocm list versions on the cli).

The main question I think remaining in this implementation is how or if we would surface the concept of "channels" in this picker.

Here is an example of how GKE surfaces analogous concepts.  Based on previous discussions, I don't think we would want to offer a "static version" choice.

jlucky@redhat.com acathrow@redhat.com