Add readme for fluentd-elasticsearch addon

cluster/addons/fluentd-elasticsearch/README.md

+# Logging Agent For Elasticsearch
+==============
+
+Logging Agent For Elasticsearch is a DaemonSet which spawns a pod on each node
+that reads logs, generated by kubelet, container runtime and containers
+and sends them to Elasticsearch, deployed in the cluster. Later logs can be
+accessed either by querying Elasticsearch directly or by using Kibana.
+
+Learn more at: https://kubernetes.io/docs/tasks/debug-application-cluster/logging-elasticsearch-kibana
+
+[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/cluster/addons/fluentd-elasticsearch/README.md?pixel)]()

cluster/addons/fluentd-gcp/README.md

@@ -2,7 +2,7 @@
 ==============
 
 Stackdriver Logging Agent is a DaemonSet which spawns a pod on each node
-that reads logs, generated by kubelet, container engine and containers
+that reads logs, generated by kubelet, container runtime and containers
 and sends them to the Stackdriver. When logs are exported to the Stackdriver,
 they can be searched, viewed, and analyzed.