To avoid lots of copy and paste lets deal with artefacts in a
template. This way we can filter out most of the pre-binary object and
library files we no longer need as we have the final binaries.

build-system-alpine also saved .git-submodule-status so for simplicity
we bring that into the template as well.

As an example the build-system-ubuntu artefacts before this patch
where around 1.3 GB, after dropping the object files it comes to 970
MB.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230228190653.1602033-23-alex.bennee@linaro.org>