Review and (implement) shared connection

From the comment in the code (SilecsCluster.h)

* \param sharedConnection = true to share the same connection with other clusters deployed on that PLC.
 * By default the sharedConnection of the cluster is false, and it uses a dedicated connection (2 channels: r/w)
 * to communicate with the controller.

however it doesn't seem implemented in completeness. TODO:

• Figure out if this functionality is beneficial (needed) and implement or remove it completely.