Prototyping costs for designs

**What do you want to see?**
An option to make the first instance of any new vehicle design (maybe also facilities) cost extra until one is completed. If you build several at once, they all cost extra.

**How would it help players?**
I dunno, I just know that certain other games (SOTS2?) use this mechanic and I guess it cuts down on compulsive upgrades, making the decision to upgrade your designs a conscious one.

**Alternatives**
This could be done at the component/mount/hull level instead, if we want. But I think doing it at the design level would be better and more intuitive.