Add Vitess example for sharded MySQL in Kubernetes.

This is a simplified version of the configs found in the Vitess repo:

https://github.com/youtube/vitess/tree/master/examples/kubernetes

Here we use a single script to start all of Vitess, since the aim is
just to show the end result. The full tutorial on our site goes into
much more detail on each step:

http://vitess.io/getting-started/

examples/vitess/create_test_table.sql

@@ -0,0 +1,8 @@
+CREATE TABLE messages (
+  page BIGINT(20) UNSIGNED,
+  time_created_ns BIGINT(20) UNSIGNED,
+  keyspace_id BIGINT(20) UNSIGNED,
+  message VARCHAR(10000),
+  PRIMARY KEY (page, time_created_ns)
+) ENGINE=InnoDB
+