[ACA-3546] Update simpleapp (#5837)
[ACA-3546] Update simpleapp (#5837)

Add forms:
* multiple attach file widget + single attach file widget
* 2 x multiple attach files widgets
* single attach file widget + multiple attach file widget
Add 3 processes with the forms above on Start event
Add a Content UI
Alfresco/alfresco-ng2-components,Alfresco/alfresco-ng2-components,Alfresco/alfresco-ng2-components,Alfresco/alfresco-ng2-components