4.x: Switch all Node API to use List instead of Set

[dkropachev]

Set - doesn't guarantee order of elements. When driver works with Nodes, say read replicas from TokenMap, Tablets, calculate replicas, API user should expect that order does matter and preserved. For that we need to switch all these APIs and internal structures to use Lists

Fix: https://github.com/scylladb/java-driver/issues/786