.gitlab-ci.yaml: Add LAVA sysota test pipeline jobs

These will, as other LAVA jobs, end up in SQUAD and, consequently,
in LAVA. It's basic tests on QEMU, running `rauc status` and `rauc
install bundle` commands and validating output.

Signed-off-by: Stevan Radaković <stevan.radakovic@linaro.org>