Add scripts for integration test setup and docs generation

* Add an OpenPGP test keypair.
 * Move script parts of documentation into script, so they can be used on a fresh Ubuntu 20.04 system
   for within a github action to setup a csaf_provider and upload documents to it for an integration test.
 * Use dineshsonachalam/markdown-autodocs in github action to automatically
   insert lines from the scripts into the docs.

Co-authored-by: Bernhard Reiter <bernhard@intevation.de>

docs/scripts/createRootCAForITest.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+# This file is Free Software under the MIT License
+# without warranty, see README.md and LICENSES/MIT.txt for details.
+#
+# SPDX-License-Identifier: MIT
+#
+# SPDX-FileCopyrightText: 2022 German Federal Office for Information Security (BSI) <https://www.bsi.bund.de>
+# Software-Engineering: 2022 Intevation GmbH <https://intevation.de>
+
+set -e
+
+mkdir -p ~/${FOLDERNAME}
+cd ~/${FOLDERNAME}
+
+certtool --generate-privkey --outfile rootca-key.pem
+
+echo '
+organization = "'${ORGANAME}'"
+country = DE
+cn = "Tester"
+
+ca
+cert_signing_key
+crl_signing_key
+
+serial = 001
+expiration_days = 100
+' >gnutls-certtool.rootca.template
+
+certtool --generate-self-signed --load-privkey rootca-key.pem --outfile rootca-cert.pem --template gnutls-certtool.rootca.template --stdout | head -1