[v1 API Review] Add `Progressing` status condition

[everettraven]

To better signal to a user when a ClusterExtension is transitioning to a new state we need to add a Progressing status condition. This condition's state does not affect the Installed condition state unless the ClusterExtension has not progressed successfully through the initial installation.

Some examples of when state transitions may occur:

• Resolving bundle to be installed for the ClusterExtension
• Unpacking bundle contents
• Installing/Upgrading resources for the ClusterExtension

Proposed Status and Reason combinations are:

• Status: False, Reason: Success - reconciliation has completed successfully, no further progression necessary
• Status: False, Reason: Blocked - error that requires manual user intervention was encountered during reconciliation. We cannot or will not progress further. As an example, the bundle image reference we resolved from a catalog is invalid (unparseable).
• Status: True, Reason: Retrying - error encountered during reconciliation that is recoverable without manual intervention. ClusterExtension is re-queued for reconciliation. Some examples of when this condition case will be populated:
  • Upgrade operation fails leaving the ClusterExtension in an intermediate state
  • Permission errors related to informer establishment

For more information, see the RFC