Add configurable layers in manifest events

Signed-off-by: Andrew Leung <anwleung@gmail.com>

configuration/configuration.go

@@ -544,6 +544,8 @@ func (auth Auth) MarshalYAML() (interface{}, error) {
 
 // Notifications configures multiple http endpoints.
 type Notifications struct {
+	// EventConfig is the configuration for the event format that is sent to each Endpoint.
+	EventConfig Events `yaml:"events,omitempty"`
 	// Endpoints is a list of http configurations for endpoints that
 	// respond to webhook notifications. In the future, we may allow other
 	// kinds of endpoints, such as external queues.
@@ -564,6 +566,11 @@ type Endpoint struct {
 	Ignore            Ignore        `yaml:"ignore"`            // ignore event types
 }
 
+// Events configures notification events.
+type Events struct {
+	ManifestLayers bool `yaml:"manifestlayers"` // include layer data in manifest events
+}
+
 //Ignore configures mediaTypes and actions of the event, that it won't be propagated
 type Ignore struct {
 	MediaTypes []string `yaml:"mediatypes"` // target media types to ignore