Currently there doesn't seem to be any way to readily identify the driver that clients are using to connect to Cassandra. Add the capability of identifying the driver through metadata information much like how HTTP Clients identify themselves through User-Agent HTTP header. This is useful for debugging in large deployments where clients tend to use different drivers, wrappers and language bindings to connect to Cassandra. This can help surface issues as well as help detect clients which are using older or unsupported drivers.
The identification information should be a string that unambiguously identifies the driver. It should include information such as the name of the driver, it's version, CQL version, Platform (Linux, macOS, Windows, etc.) and architecture (x86, x86_64).
We should surface this information in `nodetool clientstats` command.