force at least 3 head roles to be occupied during a rev round

[Drago156]

any time I've played rev since the traitor PDA for rev heads was taken out, it's always seemed like revs had no chance even with 1 or 2 security on the team, there was always like 2 heads, the captain and HoP, if not more, and the rev heads could get almost no one, and by the time they did, the heads of staff and sec team were already armed with thousands of loyalty implants, so maybe adding this along with a faster or silent rev flash would be helpful for both sides