Add support for Function and Trigger domain objects (#1060)

Vast commit, includes:

 * Introduces the Trigger domain entity.
 * Introduces the Fns domain entity.
 * V2 of the API for interacting with the new entities in swaggerv2.yml
 * Adds v2 end points for Apps to support PUT updates.
 * Rewrites the datastore level tests into a new pattern.
 * V2 routes use entity ID over name as the path parameter.

api/datastore/mock_test.go

@@ -11,5 +11,5 @@ func TestDatastore(t *testing.T) {
 	f := func(t *testing.T) models.Datastore {
 		return NewMock()
 	}
-	datastoretest.Test(t, f)
+	datastoretest.RunAllTests(t, f, datastoretest.NewBasicResourceProvider())
 }