1，添加设置群成员昵称api

2，配置当退群或者群踢人时，是否发送visible群通知

broker/src/main/java/io/moquette/imhandler/QuitGroupHandler.java

@@ -14,6 +14,8 @@ import io.moquette.spi.impl.Qos1PublishHandler;
 import io.netty.buffer.ByteBuf;
 import cn.wildfirechat.common.ErrorCode;
 
+import java.util.Set;
+
 import static win.liyufan.im.IMTopic.QuitGroupTopic;
 
 @Handler(value = QuitGroupTopic)
@@ -32,6 +34,12 @@ public class QuitGroupHandler extends GroupHandler<WFCMessage.QuitGroupRequest>
                 WFCMessage.MessageContent content = new GroupNotificationBinaryContent(request.getGroupId(), fromUser, null, "").getQuitGroupNotifyContent();
                 sendGroupNotification(fromUser, request.getGroupId(), request.getToLineList(), content);
             }
+
+            if((m_messagesStore.getVisibleQuitKickoffNotification() & 0x01) > 0) {
+                Set<String> toUsers = m_messagesStore.getGroupManagers(request.getGroupId(), true);
+                WFCMessage.MessageContent content = new GroupNotificationBinaryContent(request.getGroupId(), fromUser, null, "").getQuitVisibleGroupNotifyContent();
+                sendGroupNotification(fromUser, request.getGroupId(), request.getToLineList(), content, toUsers);
+            }
         }
         return errorCode;
     }