Refactor command system

PluralKit.Bot/CommandSystem/CommandGroup.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+
+namespace PluralKit.Bot.CommandSystem
+{
+    public class CommandGroup
+    {
+        public string Key { get; }
+        public string Description { get; }
+        
+        public ICollection<Command> Children { get; }
+
+        public CommandGroup(string key, string description, ICollection<Command> children)
+        {
+            Key = key;
+            Description = description;
+            Children = children;
+        }
+    }
+}