Add basic application framework and example application to show interaction between events an NBI

Depends on:

• !340 (merged)
• !344 (merged)
• !349 (merged)
• !342 (merged)

controller/event/event.go

@@ -9,14 +9,16 @@ type Event struct {
 	Type     string    `json:"type,omitempty"`
 }
 
-// TypeAdd is an add event.
-const TypeAdd = "add"
+const(
+    // TypeAdd is an add event.
+    TypeAdd = "add"
 
-// TypeUpdate is an update event.
-const TypeUpdate = "update"
+    // TypeUpdate is an update event.
+    TypeUpdate = "update"
 
-// TypeDelete is a delete event.
-const TypeDelete = "delete"
+    // TypeDelete is a delete event.
+    TypeDelete = "delete"
+)
 
 // NewAddEvent creates a new add event.
 func NewAddEvent(entityID uuid.UUID) Event {