Moved properties to engine layer

engine/properties.go

@@ -0,0 +1,12 @@
+package engine
+
+type Property struct {
+	Id    string
+	Value string
+}
+
+type PropertyRepository interface {
+	Put(id string, value string) error
+	Get(id string) (string, error)
+	DefaultGet(id string, defaultValue string) (string, error)
+}