Added trigger component like custom form control

• Added new wrapper of type page, using NavigationController to navigate. Now, you can do something like this:

constructor(monthPickerCtrl: IonicMonthPickerController) { }

openPicker() {

   const picker = this.monthPickerCtrl.create({
     container: {
          type: 'page'
     }
  });

 picker.present();
}

Or use like a component tag selector

<ion-monthpicker-trigger [container]="{ type: 'page' }"> </ion-monthpicker-trigger>

• Changed IonicMonthPickerTriggerComponent to use ControlValueAcessor Angular interface, and transform them to a custom FormControl. This allow change component state by form.controls['fieldName'].setValue('myMonth') and track form validation

• Removed the afterRender event from trigger component. This is not necessary anymore, because you can subscribe for Reactive Form events (change, blur...)