Integrate gitlab-ci/lpag/add_rpi_qemu

Commit: https://git.seco.com/edgehog/infrastructure/gitlab-ci/-/commit/f2c40bcc6aceabcc7d96ad9cf2773ef9a8d6638f

[RASPBERRY] Add support to Raspberry Pi 4 machine

• The Raspberry Pi 4 machine only supports U-Boot in Edgehog Things distro, for this reason we introduce a check on the presence of U-Boot files and eventually not deploy the package in case no files are found.
• At build time, we only check the number of U-Boot artifacts and give a warning if they are less than expected.

.gitlab-ci

-Subproject commit eade2597502ca78fa045400040b584d390765d36
+Subproject commit f2c40bcc6aceabcc7d96ad9cf2773ef9a8d6638f