docs: add diagrams for marker interface, master-worker, mediator, memento, metadata mapping, microservices api gateway, microservices log aggregation, monad, monitor, monostate, multiton, mute idiom

memento/README.md

@@ -36,6 +36,10 @@ Wikipedia says
 
 > The memento pattern is a software design pattern that provides the ability to restore an object to its previous state (undo via rollback).
 
+Sequence diagram
+
+![Memento sequence diagram](./etc/memento-sequence-diagram.png)
+
 ## Programmatic Example of Memento Pattern in Java
 
 In our astrology application, we use the Memento pattern to capture and restore the state of star objects. Each state is saved as a memento, allowing us to revert to previous states as needed.