Add system test for dnssec-keyfromlabel

Add missing system test for dnssec-keyfromlabel. Test for various
algorithms that we can generate key files from a key that is stored in a
HSM, and that those keys can be used for signing with dnssec-signzone.

bin/tests/system/keyfromlabel/prereq.sh

@@ -0,0 +1,21 @@
+#!/bin/sh -e
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+. ../conf.sh
+
+if [ -n "${SOFTHSM2_MODULE}" ] && command -v softhsm2-util >/dev/null; then
+	exit 0
+fi
+
+echo_i "skip: softhsm2-util not available"
+exit 255