Use per CF-id reference count instead, and use handles as result of
add operations. These must either be explicitly released or stored
(rp_set), or they will release the corresponding replay_position
upon destruction.
Note: this does _not_ remove the replay positioning ordering requirement
for mutations. It just removes it as a means to track segment liveness.
Refs #1813 (fixes scylla part)
Added require_client_auth and priority_string options to
server_encryption_options/client_encryption_options an process them.
Allows TLS method/algo specification. Also enabled enforcing known cert
authentication for both node-to-node and client communication.