Modal: string argument to the open method is confusing

See http://stackoverflow.com/q/39464345/1418796

Really, the string argument is only good for unit-testing but not for any real-life applications. We should remove it altogether or at least clarify in the docs.

On top of this we need to support components as arguments to the open method, see #680

[SanderElias]

My vote would go on removing the string argument completely, as it’s just utterly confusing. Adding the component support to the open method makes a lot of sense. This will take out quite some boileplate code that is now needed to support the usecase of #680

[felixfbecker]

How about something like

ngbModal.open(MyModalComponent).then(value => ...

where the component is passed the modal instance as an @input?

to avoid having to specify @Input it could also be possible to subclass a ModalComponent:

import {ModalComponent} from '@ng-bootstrap/ng-bootstrap'

@Component({})
class MyModalComponent extends ModalComponent {
  ngOnInit() {
    this.modal.close(value) // or
    this.modal.dismiss(value)
  }
}

where ModalComponent is something like:

abstract class MyModalComponent {
  @Input()
  public modal: ModalInstance
}