add Base Decorators library

[LeoVS09]

Adding Base Decorators to utilities section.

This library provides primitives that simplify decorators writing in typescript. So it can be written in few lines:

import { OnReturnHook } from 'base-decorators';

class Service {

  @OnReturnHook(({ result }) => console.log('Result is', result))
  greet(name: string) {
    return `Hello, ${name}`;
  }
}

Hope that your are interesting in sharing this library.