Check if a new node can fulfil the XDCR requirements it takes to be in the cluster.

This ticket is related to MB-16285 but targeted towards XDCR.

In support we have seen cases where a customer adds a new node to the cluster and XDCR stops working on the new node. Most of the time it is because the firewall has not been updated for the new node.

Before a node is accepted into the cluster it should be tested to ensure it does have access to contact all the nodes in the target cluster.