New collision preset

I think it would be useful to have a collision preset for items that prevents collision with entity that the entity is attached to.

For example, if you attach a sword to a player, you could set the collision preset to “Collide with All but Parent”.

The actual usecase that brought this one is players holding platforms that other players can use to reach higher areas. For example, someone could pick up a square platform, move below a too-high-to-reach area, and player 2 would use the held entity as the step ladder to reach it.