Add initial support for reusing the Mesa CI infrastructure.
Note this doesn't conflict with the old CI since it doesn't share the
'ci/' folder, but instead uses '.gitlab-ci/', which makes the new setup
consistent with Mesa CI.
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>