Add new props into PropFactory

[Madecu]

We need a semi-automatic way to add all the props we have, as well as the new ones we're going to create, to the PropFactory Blueprint.

[Youngzipper]

use UE4?

[Madecu]

We are going to work with Editor Utilities Blueprints in UE5 but I think most of the nodes and functions we will use for that will work in UE4 too. Don't know yet, we haven't started the task.