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

monitor/README.md

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 > In concurrent programming (also known as parallel programming), a monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become false. Monitors also have a mechanism for signaling other threads that their condition has been met.
 
+Sequence diagram
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+![Monitor sequence diagram](./etc/monitor-sequence-diagram.png)
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 ## Programmatic Example of Monitor Pattern in Java
 
 The Monitor design pattern is a synchronization technique used in concurrent programming to ensure that only one thread can execute a particular section of code at a time. It is a method of wrapping and hiding the synchronization primitives (like semaphores or locks) within the methods of an object. This pattern is useful in situations where race conditions could occur.