#ormus - simple observer module

[AmirAtashghah]

add simple pubsub mechanism with goroutines & channels
https://laravel.com/docs/10.x/events
https://refactoring.guru/design-patterns/observer
https://itnext.io/observer-pattern-in-go-withchannels-b35b1deaa438#:~:text=Channels%20provide%20a%20robust%20means,the%20subject%20and%20its%20observers.
https://github.com/imkira/go-observer
observer pattern design guru