gitlab: Move board coverage to a template
gitlab: Move board coverage to a template

This will allow us to build coverage reports for multiple boards.

Also add the `coverage` keyword, so the coverage of each step will
appear on the jobs page. I.e.
https://gitlab.com/zephyr-ec/ec/-/pipelines/380049325/builds

BRANCH=None
BUG=None
TEST=None

Change-Id: I892653406f471b3c98ad6dbd7cb91c086614e264
Signed-off-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3197731
Commit-Queue: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Tested-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec