move admin check to ContextChecksExt, allow pk;debug proxy for staff in support server

PluralKit.Bot/CommandSystem/ContextChecksExt.cs

@@ -1,3 +1,7 @@
+using System.Linq;
+
+using Autofac;
+
 using Myriad.Types;
 
 using PluralKit.Core;
@@ -52,5 +56,19 @@ namespace PluralKit.Bot
                 throw new PKError($"You must have the \"{permissionName}\" permission in this server to use this command.");
             return ctx;
         }
+
+        public static bool CheckBotAdmin(this Context ctx)
+        {
+            var botConfig = ctx.Services.Resolve<BotConfig>();
+            return botConfig.AdminRole != null && ctx.Member != null && ctx.Member.Roles.Contains(botConfig.AdminRole.Value);
+        }
+
+        public static Context AssertBotAdmin(this Context ctx)
+        {
+            if (!ctx.CheckBotAdmin())
+                throw new PKError("This command is only usable by bot admins.");
+
+            return ctx;
+        }
     }
 }