'system.status' and 'system.describe_ring' are imperfect names for
what they do, so rename them. Fortunately they aren't exposed in any
released version so there is no compatibility concern.
Closes#9530
* github.com:scylladb/scylla:
system_keyspace: rename 'system.describe_ring' to 'system.token_ring'
system_keyspace: rename 'system.status' to 'system.cluster_status'