Improve the current scoring system for the murderer

[AKMDM]

Improve the current way the murderer's score is calculated at the end of a round. Perhaps it's too easy for a murderer to earn 100%, so add a difficulty option for the server.

Sometimes, a murderer can even score 100% without necessarily winning. There can always be that one last innocent that survives, but still earns a perfect score regardless.

Also, Prepper has created some new medals that can be awarded to the murderer based on their item usage. For example, using bertholite canisters or smoke bombs excessively can earn them a unique medal corresponding to that item.