Added a stop command

I found the absence of a stop command particuraly annoying so i implemented it in 10 minutes

src/main/java/emu/lunarcore/command/commands/StopCommand.java

@@ -0,0 +1,20 @@
+package emu.lunarcore.command.commands;
+
+
+import emu.lunarcore.command.Command;
+import emu.lunarcore.command.CommandArgs;
+import emu.lunarcore.command.CommandHandler;
+
+@Command(label = "stop",
+    aliases = {"exit"},
+    permission = "admin.stop",
+    requireTarget = false,
+    desc = "/stop - Stops the server")
+public class StopCommand implements CommandHandler {
+
+    @Override
+    public void execute(CommandArgs args) {
+        args.sendMessage("Stopping server");
+        System.exit(1000);
+    }
+}