Introduce kcmutils class

kcmutils now uses a mandatory runtime dependency during build, which for
convenienc is provided by this new class.

classes/kcmutils.bbclass

@@ -0,0 +1,12 @@
+# Class for recipes using kcmutils host tools
+#
+# SPDX-FileCopyrightText: 2022 Andreas Cord-Landwehr <cordlandwehr@kde.org>
+#
+# SPDX-License-Identifier: MIT
+
+DEPENDS:append = " \
+    kcmutils \
+    kcmutils-native \
+"
+
+EXTRA_OECMAKE:append = " -DKF5_HOST_TOOLING=${STAGING_DIR_NATIVE}/${libdir}/cmake"