Added new Server.broadcast method to broadcast to specific groups of users, including non-players

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/Bukkit.java

@@ -219,4 +219,8 @@ public final class Bukkit {
     public static void shutdown() {
         server.shutdown();
     }
+
+    public int broadcast(String message, String permission) {
+        return server.broadcast(message, permission);
+    }
 }