Attempt to reconnect existing keystore when creating cluster from backup

Add support for being able to create a cluster from a backup and automatically reconnect an existing disconnected keystore that was associated with the cluster from which the backup was made.

The template currently supports creation of a new CloudHSM cluster from a backup when `pStackScope` is set to `cluster-and-client-only`, but support has not been added to enable the same operation when the scope is set to `with-custom-key-store`. Currently, under that condition, the template will create a new custom keystore and connect it to the newly instantiated cluster. The desire is to at least have an option to attempt to reconnect an existing keystore to the new cluster.