Feature: global bootstrap for browser rendering

[trotyl]

Current

One can only mount elements in existing Angular component.

Expected

Support global bootstrap without any Angular code, like:

import { createElement, render } from 'ng-renderable'
import 'ng-renderable/browser'

render(<p>Hello World!</p>, document.querySelector('#main'))

Note: the only dependency should be @angular/core, not use @angular/platform-browser.