Dynamic and granular message subscription over message bus

[rtnpro]

Currently, we subscribe to all messages over message bus, which works pretty well for WRITE operations to keep the systems updated about the latest changes. But, this does not work well for READs as these are many in number and other's don't need to know about it, but the client requesting the data. Also, we need to find out a way to subscribe (unsubscribe) to(from) TOPICS without latency in setting up the duplex communication channel.