Law: Consume Dust to increase Hero exp gains

This would help create a gameplan based on dust generation. A few implementations:

-Consume a flat amount per hero (based on level), multiplicatively increases exp gains

-Consume all dust income, convert to exp and divide amongst all heroes

-Consume all dust income, and give a multiplicative exp bonus to all heroes, scaling with the amount consumed

Owning the Academy could unlock an improved version of this law, since they likely have specialized equipment for this.