Add 'Lezione 08'

_posts/2022-10-26-Patterns.md

src/08_patterns/00_index.md

src/08_patterns/01_meta-patterns.md

src/08_patterns/02_singleton.md

src/08_patterns/03_iterator.md

src/08_patterns/04_chain-of-responsibility.md

src/08_patterns/05_flyweight.md

src/08_patterns/06_nullobject.md

src/08_patterns/07_strategy.md

src/08_patterns/08_observer.md

src/08_patterns/09_adapter.md

src/08_patterns/10_facade.md

src/08_patterns/11_composite.md

src/08_patterns/12_decorator.md

src/08_patterns/13_state.md

src/08_patterns/14_factory.md

src/08_patterns/15_abstract-factory.md

src/08_patterns/16_mvc.md

src/08_patterns/17_mvp.md

src/08_patterns/18_builder.md