Legacy mode: emulate previous SE games

**What do you want to see?**
FrEee is designed to emulate Space Empires IV. But what if it had a legacy mode that loaded a special mod that made it behave like SE3, SE2, or even SE1?

**How would it help players?**
Just for fun 🙂 Also give us smaller goals to work toward!

**Alternatives**
Maybe even some SE5 features like hexes?

**Screenshots and mockups**
N/A

**Things to consider**
N/A