Goal
Improve channel UX in cluster settings for the following scenarios:
1, when no channels are selected (not configured)
2, when no channel is available 
3, when recovering from unknown versions

Acceptance Criteria

• On cluster settings details, when no channels are selected (not configured), make the message more informative and actionable.
  • Use an information icon along with a message like, "Not configured to request update recommendations" under the update status.
  • Change the call to action under "Channel" from "-" to "Not configured"
  • add an informational alert that says something like "This cluster is not currently requesting update recommendations. To request update recommendations, configure a channel."
  • in the update channel modal (WIP):
    • repeat the informational alert
    • begin the descriptive paragraph with: "We have found your current version in the channels listed in the dropdown below."
• On cluster settings details, when no channel is available (eg. a nightly build), change the update status to be more informative an actionable.
  • Use an information icon along with a message like "Update recommendations are not available."
  • Add an informational alert that says something like: " Nightly builds are not available in any update channel. You can reference the OpenShift Container Platform release statues for more build information."
    • Link to the public facing release status url (need to confirm if we actually want to surface this in console)
  • Change the description under "Channel" to "No available channels"
• On the cluster settings details, when users are trying to recover from unknown versions (perhaps they forced an upgrade in the CLI and find themselves back in the UI with a selected channel that their version is not in), change the update status to be more informative and actionable.
  • Maintain the current error icon along with a message like "Current version not found."
  • add an error alert that says something like: "Current version 4.6.1 is not found in stable-4.5. To request update recommendations, configure a channel that supports your current version."
  • in the Update channel modal (WIP):
    • repeat the error alert
    • begin the descriptive paragraph with: "we have found your current version in the channels listed in the dropdown below."
    • disable the incompatible channel (both the text and the selection)
    • add a horizontal line to separate the incompatible channel from the channels that we have found your current version in

Of note: clearing channels is our recommended approach for "I don't want my CVO talking to the upstream". See the long-in-flight docs#22252. 

Design

• Design Story: https://issues.redhat.com/browse/PD-579
• Marvel: https://marvelapp.com/prototype/5h09eic
• Design PR: https://github.com/openshift/openshift-origin-design/pull/511