Ability to point to sprites and sound files via expressions instead of direct filenames.

[VanCastar]

We'd REALLY need to be able to make pointing to sprites and sound files via expressions instead of direct filenames.

Why?
The problem arises when trying to animate 3d box faces.
At the moment I have a game project that has hundreds of animation faces for the 3d box faces and I need to add them all into the events manually one by one like this.

Instead of being able to do a loop that changes the face by expression with counter for example.
"Graphics\Sprites\Fog_" + ToString(Variable(Number)) + ".png"

This same problem arises with using sound effects too with a big variety of sounds used in relation to some actions.

It was quite well discussed in GDevelop discord under this link.

This problem arose with my most recent game project that resulted only the animation changes to take 10 times the events than the rest of the game (and also the time manually changing them).
Larger problem rose after that when I needed to reset the naming convention and had to do the changes to them manually all over again for hundreds of events one by one.