3.x: Make LWT routing consider dc and rack priority same way it is done for regular queries

[dkropachev]

Currently LWT routing relay on Metadata.getReplicasList:

https://github.com/scylladb/java-driver/blob/6a8678fd99950282e265a65ba0b661d23dfc8bdb/driver-core/src/main/java/com/datastax/driver/core/RequestHandler.java#L146-L154

https://github.com/scylladb/java-driver/blob/6a8678fd99950282e265a65ba0b661d23dfc8bdb/driver-core/src/main/java/com/datastax/driver/core/RequestHandler.java#L98-L132

https://github.com/scylladb/java-driver/blob/6a8678fd99950282e265a65ba0b661d23dfc8bdb/driver-core/src/main/java/com/datastax/driver/core/Metadata.java#L591-L618

Which does not respect rack or DC prioritization, we need to fix it to priorities nodes same way it is done for regular queries. Best solution would be to move all this logic into LoadBalancing policy.