`ocm create cluster` should have a json output

[georgettica]

sometimes we want to script ocm create cluster and I don't want to

$ OCM_CREATE=$(ocm create cluster ${CLUSTER_NAME})
$ CLUSTER_ID=$(echo $OCM_CREATE | grep '^ID:' | awk '{print $2}')

and something along the lines of

$ OCM_CREATE_JSON=$(ocm create cluster ${CLUSTER_NAME} --output=json )
$ CLUSTER_ID=$( echo $OCM_CREATE | jq .id )