Add a keyset KMIP test subcommand.

E.g. `dnst keyset kmip test-server <server_id>`.

This would verify the operations that keyset needs to perform, e.g. generate key pair, get dnskey, sign, destroy (and list keys?), and for each supported algorithm.

It should clean up after itself.

This is not intended to be a speed test but rather a functionality test.

Should it also test with different key id/label lengths?