Add histogram aggregator plugin (#2387)

etc/telegraf.conf

@@ -606,6 +606,32 @@
 #   drop_original = false
 
 
+# # Configuration for aggregate histogram metrics
+# [[aggregators.histogram]]
+#   ## General Aggregator Arguments:
+#   ## The period on which to flush & clear the aggregator.
+#   period = "30s"
+#   ## If true, the original metric will be dropped by the
+#   ## aggregator and will not get sent to the output plugins.
+#   drop_original = false
+#
+#   ## The example of config to aggregate histogram for all fields of specified metric.
+#   [[aggregators.histogram.config]]
+#     ## The set of buckets.
+#     buckets = [0.0, 15.6, 34.5, 49.1, 71.5, 80.5, 94.5, 100.0]
+#     ## The name of metric.
+#     metric_name = "cpu"
+#
+#   ## The example of config to aggregate for specified fields of metric.
+#   [[aggregators.histogram.config]]
+#     ## The set of buckets.
+#     buckets = [0.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0, 100.0]
+#     ## The name of metric.
+#     metric_name = "diskio"
+#     ## The concrete fields of metric
+#     metric_fields = ["io_time", "read_time", "write_time"]
+
+
 
 ###############################################################################
 #                            INPUT PLUGINS                                    #