ng-content and compound components practice

• Multiple ng-content can be done with different select on the parent component. Reference
• This is needed if you need the child component:

  <ng-content select="rd-empty-state-title"></ng-content>
  <ng-content select="rd-empty-state-text"></ng-content>

• Simple <ng-content></ng-content> child components can work, too.
• ContentChild is needed if you want to control HTML projected inside the component. This uses afterContentInit hook.