Allow specifying simple-ent-force/owner variant in ghost/bps

[Nexela]

Allow specifying the simple entity variant in ghosts / blueprints / create_entity When set the revived entity would switch to that variant instead of a random one.

Additionaly having the current image variant being the one that shows up as the ghost image would be awesome but not a game breaker if this is not possible.

[Earendel]

This would be extremely useful for me too.