Suggestion: Allow modifying the War Sickness feature

[Parthodys]

Is your feature request related to a problem? Please describe.
The problem is that the current "Health 1, Nausea V, Poison V, Weakness V, Slowness III, Mining Fatigue III", do not actually kill players or otherwise prevent them from showing up and causing problems as an outsider.
Weakness V for example does not prevent damage with bows, which means you can sit further from battle and just pelt the enemies with arrows from relative safety.

We'd prefer different settings for it, so perhaps if we'd be able to modify the effects or execute commands on players that are within the sickness zone, we would be able to make it more effective.

Describe the solution you'd like
Allow modifying the sickness effects or executing commands on sick players.

Describe alternatives you've considered
I've considered causing players who are in the area to take 1 heart of damage with other plugins, but this unfortunately also damages those participating in the war. There might be some trick around it, but I don't see why SiegeWar doesn't just let us decide, as there could also be other kind of settings, such as just giving a disadvantage to outsiders, rather than punishing them more.