Support manual savepoint redeploy for jobs and deployments

A common request is to support a streamlined, user friendly way of redeploying from a target savepoint.

Previously this was only possible by deleting the CR and recreating it with initialSavepointPath. A big downside of this approach is a loss of savepoint/checkpoint history in the status that some platforms may need, resulting in non-cleaned up save points etc.

We suggest to introduce a `savepointRedeployNonce` field in the job spec similar to other action trigger nonces.

If the nonce changes to a new non null value the job will be redeployed from the path specified in the initialSavepointPath (or empty state If the path is empty)