testing updates

 - tweak .gitpublish base to origin/master
 - restore .gitmodules to qemu-project hosts
 - drop 64 bits guests from i686
 - update aarch64/s390x custom runners to 24.04
 - tweak gitlab-runner registration method
 - make check-venv dependency for functional tests
 - replace avocado's gdb support with pygdbmi
 - remove avocado dependencies from reverse_debug tests
 - ensure replay.bin doesn't loose events after SHUTDOWN_HOST_QMP