feat: new library Software design patterns

[excalibot]

Design patterns icons from https://refactoring.guru/design-patterns/catalog

Submitted by Thomas de Saint Exupery

Items: Visitor pattern, Template method pattern, Strategy pattern, State pattern, Command pattern, Observer pattern, Mediator pattern, Iterator pattern, Chain of responsability pattern, Flyweight pattern, Composition pattern, Proxy pattern, Facade pattern, Singleton pattern, Decorator pattern, Prototype pattern, Memento pattern, Builder pattern, Bridge pattern, Adapter pattern, Abstract factory pattern, Factory pattern

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