ci: Introduce workflow for compliance

It includes jobs for checking DCO and reuse. The latter is set to allow
fails as the repository is not yet reuse compliant. When that is done,
we can switch it.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

.github/workflows/docker-images/utils.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# SPDX-FileCopyrightText: Andrei Gherzan <andrei.gherzan@huawei.com>
+#
+# SPDX-License-Identifier: MIT
+
+_log() {
+	_level="$1"
+	_msg="$2"
+	echo "[$_level] $_msg"
+}
+
+error() {
+	_msg="$1"
+	_log "ERR" "$1"
+	exit 1
+}
+
+warn() {
+	_msg="$1"
+	_log "WRN" "$1"
+	exit 1
+}
+
+log() {
+	_msg="$1"
+	_log "LOG" "$1"
+}