Add cluster_info struct containing cluster_name, partitioner, and snitch_name.
Implement describe_cluster() method to provide cluster metadata by combining
data from gossiper (cluster_name, partitioner) and snitch (snitch_name).
It will be used by next patch
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
53361358ef