Sync message for the group chats and group chat messages

...la/org/bigbluebutton/core/apps/groupchats/GroupChat.scala

...g/bigbluebutton/core/apps/groupchats/GroupChatHdlrs.scala

...on/core/apps/groupchats/SyncGetGroupChatMsgsMsgHdlr.scala

...utton/core/apps/groupchats/SyncGetGroupChatsMsgHdlr.scala

...main/scala/org/bigbluebutton/core/models/GroupChats.scala

...n/scala/org/bigbluebutton/core/running/MeetingActor.scala

.../org/bigbluebutton/core2/FromAkkaAppsMsgSenderActor.scala

...in/scala/org/bigbluebutton/common2/msgs/GoupChatMsg.scala