[DNR] add yubikey smartcard modules

[py4chen]

PR adds authentication and csr modules for yubikey based certificates generation.

{
    "keyid_version": 1,
    "sshca_failure_dir": "/dev/shm/sshcafailures/",
    "sshca_failure_timeout": 3600,
    "sshca_failure_retry": 5,
    "handlers":
    {
        "smartcard":
        {
            "authn": [
                {
                    "module": "f9_verify",
                    "f9_certs_dir": "/opt/sshca/RA/f9_certs/"
                },
                {
                    "module": "slot_attest",
                    "slot": "9a",
                    "piv_root_ca": "/opt/sshca/RA/piv_root_ca.pem",
                    "u2f_root_ca": "/opt/sshca/RA/u2f_root_ca.pem",
                },
                {
                    "module": "slot_attest",
                    "slot": "9e",
                    "piv_root_ca": "/opt/sshca/RA/piv_root_ca.pem",
                    "u2f_root_ca": "/opt/sshca/RA/u2f_root_ca.pem",
                },
                {
                    "module": "slot_serial",
                    "slot": "9e",
                    "yubikey_mappings": "/opt/sshca/RA/yubikey_mappings",
                },
            ],
            "csr":  [
                {
                    "module": "smartcard_hardkey",
                    "_comment": "touchSSH",
                    "is_firefighter": false,
                    "touch_policy": 3,
                    "principals": "<logname>,<logname>:touch",
                    "slot": "9e",
                    "cert_validity_sec": 86400
                }
            ],
            "key_identifiers": {
                "default": "ssh-user-key-secondary",
                "rsa": "ssh-user-key",
                "ecdsa": "ssh-user-key-secondary"
            }
        }
    },
    "signer":
    {
        "crypki_port": 4443,
        "crypki_endpoints":
        [
            "crypki.tp2.prod.sshca.ouryahoo.com",
            "crypki1.tp2.prod.sshca.ouryahoo.com",
            "crypki2.tp2.prod.sshca.ouryahoo.com",
            "crypki3.tp2.prod.sshca.ouryahoo.com"
        ],
        "ysshura_user": "ysshura",
        "tls_client_key_file": "/opt/sshca/RA/tls_client.key",
        "tls_client_cert_file": "/opt/sshca/RA/tls_client.crt",
        "tls_ca_cert_files":
        [
            "/opt/sshca/RA/tls_ca.pem"
        ],
        "retries": 3
    }
}

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