Improve `lcb_get_replica()`. Now it is possible to choose between three strategies:
LCB_REPLICA_FIRST: Previously accessible
and now the default, the caller will get a reply from the
first replica to successfully reply within the timeout for
the operation or will receive an error.
LCB_REPLICA_ALL: Ask all replicas to send
LCB_REPLICA_SELECT: Select one replica by
the index in the configuration starting from zero. This
approach can more quickly receive all possible replies for a
given topology, but it can also generate false negatives.
Note that applications should not assume the order of the replicas indicates more recent data is at a lower index number. It is up to the application to determine which version of a document/item it may wish to use in the case of retrieving data from a replica.