While work on this epic was completed, the new code was only available if the user put in a URL flag (newclusterlist=true).

The purpose of this story is to remove the need for the URL flag so all traffic to the cluster list goes to the new code using the new data fetching method.

This is the final step in order to remove code duplication of the cluster list

NOTE:  This is not a change to view the regionalized cluster list (see Epic 1526).  To view the regionalized cluster list,  a feature gate and a URL flag (multiregion=true) will still be required.

NOTE: The cluster actions will continue to be the current Redux-based cluster actions.

Technical tasks:

• Change routing
• Remove newClusterList URL flag code
• Remove new cluster list preview banner
• Archive old cluster list code including unused reducers.

Testing implications:

The only user-facing change is to verify that the cluster list is showing when the user goes to `/openshift/cluster-list`.  Test of the functionality of the newclusterlist have been done as part of other Jira stories.