Self-managed HostedCluster guided updates

Today there is no tooling to guide users when updating their HostedCluster. This is in contrast to standalone OCP which provides multiple guided paths for users who are updating their cluster via the the UI and CLI.

The HostedCluster update process is complicated to get right, even for advanced users. Successfully updating a HostedCluster requires getting three dimensions right.

1. The targeted release-image should be part of the cincinnati update recommendations for the currently deployed release image.
2. The targeted release-image needs to be supported by the hypershift-operator on the management OCP cluster which reconciles the HostedCluster
3. The targeted release-image used by the HostedCluster and NodePool resources need to either match, or adhere to our skew policy. Essentially we don't want someone to be able to update their HostedCluster or NodePools in ways that are incompatible with one another.