Add LethalConfig with suitable custom options

The custom callback attempts to prevent modifications mid-round. Use
IsHost to check for permissions, as IsClient is always true for
everyone even in local single-player setting.

There is a bug in LethalConfig which makes it possible to modify entries
bypassing the callback once per round, but it is pretty hard to abuse:
https://github.com/AinaVT/LethalConfig/issues/60

MuzikaGromche/Plugin.cs

@@ -307,7 +307,7 @@ namespace MuzikaGromche
                 var slider = new IntSliderConfigItem(track.Weight.Entry, new IntSliderOptions
                 {
                     RequiresRestart = false,
-                    CanModifyCallback = CanModifyCallback,
+                    CanModifyCallback = CanModifyWeightsNow,
                 });
                 LethalConfigManager.AddConfigItem(slider);
             }
@@ -323,7 +323,7 @@ namespace MuzikaGromche
             ConfigManager.Register(this);
         }
 
-        public static CanModifyResult CanModifyCallback()
+        public static CanModifyResult CanModifyWeightsNow()
         {
             var startOfRound = StartOfRound.Instance;
             if (!startOfRound)