.github: implement reusable workflows
.github: implement reusable workflows

The workflow was implemented as a reusable workflow in oe-rpb-manifest
repo, let's use it from there instead of duplicating the same workflow
in many places.

Signed-off-by: Nicolas Dechesne <05fca36dfcf68f7e1c9eaf62b074676ab50a133b@linaro.org>

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