Create public and private ssh-keys.

def generate_rsa_key_pair():
    """Create public and private ssh-keys."""

    key = rsa.generate_private_key(
        backend=default_backend(), public_exponent=65537, key_size=2048)

    public_key = key.public_key().public_bytes(
        serialization.Encoding.OpenSSH,
        serialization.PublicFormat.OpenSSH).decode("utf-8")

    pem = key.private_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PrivateFormat.TraditionalOpenSSL,
        encryption_algorithm=serialization.NoEncryption()).decode("utf-8")

    return public_key, pem