Adding a config message proto.

This will be used to advertise configuration changes to voltha's pub/sub
system. Notifications will emerge from the same place proxy notifications
come from.

Change-Id: I89f8ed9e4fbd3ccabf07c87765234c5ed49c6934
diff --git a/voltha/protos/events.proto b/voltha/protos/events.proto
index 5f95b7f..5052a96 100644
--- a/voltha/protos/events.proto
+++ b/voltha/protos/events.proto
@@ -4,7 +4,22 @@
 
 import "meta.proto";
 import "google/api/annotations.proto";
+import "google/protobuf/any.proto";
 
+message ConfigEventType {
+    enum ConfigEventType {
+        add = 0; // A new config has been added
+        remove = 1; // A config has been removed
+        update = 2; // A config has been updated
+    }
+}
+
+message ConfigEvent {
+    ConfigEventType.ConfigEventType type = 1;
+
+    string hash = 2; // hash for this change, can be used for quick lookup
+    google.protobuf.Any data = 3; // the actual new data, may be empty for a remove operation
+}
 
 message KpiEventType {
     enum KpiEventType {