Finalize cluster context switcher design

Refine the visual styling of the dropdown and the various states, aligning more closely with the upcoming Project switcher design.

Finalize the behavior of the Create Cluster button when ACM is and isn’t installed - do we point folks to OCM to create clusters instead? Do we duplicate OCM's Create page in-Console? Should OCM be hub-aware and point users to the ACM hub that manages that cluster to create a new one in the same family? Do we want to highlight that the ACM operator provides the ability to switch within the dropdown?

Consider how to handle clusters that are visible to ACM but may be in weird states like installing, hibernated, etc. which wouldn’t show any useful information within the single-cluster Admin/Dev perspectives. Maybe a unique empty state could be shown if a cluster enters one of those states while the user is in its context.

Dropdown states:

• New clusters
  • ACM is not installed anywhere; install it to enable switching
• Spoke clusters
  • ACM is available at the hub; go to that UI to switch clusters easily
• Hub clusters
  • Switch clusters easily just like you can with Projects

Design

• Slide deck

Links

• (Slack) Mention of the ability to "favorite" clusters and access them quickly from ACM (and maybe launch a separate Console to more easily compare resources side-by-side, until/unless we devise something better)