Select Detrimental Character options before game

[kimhanm]

Is your feature request related to a problem? Please describe.
The Detrimental Characters Variant can sometimes be not a big hurdle and other times be incredibly difficult.
It would be nice to have a more granular difficulty setting with this variant.

Describe the solution you'd like
It would be nice if one could constrain which characters can appear before the game starts. For example by introducing commands to toggle/set which characters may/may not appear.

A simple interface could be something like

• /characters list (enabled|disabled|all): lists (enabled|disabled|all available) characters
• /characters remove [character] removes selected characters, removes all if no argument is given
• /characters add [characters] add selected characters, adds all available if no argument is given
  which are disabled unless the detrimental characters option is set.