do not require traitor/detective/innocent trichotomy

[EntranceJew]

Is your feature request related to a problem? Please describe.

the base-game classes are tightly coupled to role distribution logic preventing Infected-only rounds, or separating Detective from other role distribution

Describe the solution you'd like

something that uses some of the older code from previous commits here

Describe alternatives you've considered

i don't know, apparently a complete rewrite is pending but nothing is actively planned where i can see it

Additional context

this is placing undue emphasis on the requirements for #1262 as a lot of people keep asking about how our server handles defective and infected logic, and in my opinion that should be a randomat event rather than something that touches TTT2ModifyFinalRoles but everything that wants to do that has to touch it if it isn't accommodated for by role-distribution