CI: add sbom generation on Linux

Use the Yocto class to generate SBOM. Activate on Linux only,
there is a pending issue on Zephyr [1]

[1] https://lists.openembedded.org/g/openembedded-core/message/167450



Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>