metrics: scaling: add datestamps to stats samples

Add invididual date entries to each statistics sample, to
suppliment the top level date entry. This helps order the
samples if we are flattening the data into say Elasticsearch.

Signed-off-by: Graham Whaley <graham.whaley@intel.com>

metrics/scaling/k8s_parallel.sh

@@ -102,6 +102,10 @@ save_stats() {
 
 	local json="$(cat << EOF
 	{
+		"date": {
+			"ns": $(date +%s%N),
+			"Date": "$(date -u +"%Y-%m-%dT%T.%3N")"
+		},
 		"n_pods": {
 			"Result": ${n_pods},
 			"Units" : "int"

metrics/scaling/k8s_scale.sh

@@ -46,6 +46,15 @@ grab_stats() {
 	local mem_free=()
 	info "And grab some stats"
 
+	local date_json="$(cat << EOF
+			"date": {
+				"ns": $(date +%s%N),
+				"Date": "$(date -u +"%Y-%m-%dT%T.%3N")"
+			}
+EOF
+	)"
+	metrics_json_add_array_fragment "$date_json"
+
 	local pods_json="$(cat << EOF
 			"n_pods": {
 				"Result": ${n_pods},