lava: Merge the job templates from apertis-tests

Keeping the LAVA job templates in apertis-tests has many problems.

Since apertis-tests is also a package, updates for stable releases should go through -updates branches, but that plays badly with the image building recipes as they only pull from the the main branch.

Correctly tracking which revision of the tests has been used on a specific pipeline run is also specific attention.

Testing changes to the templates is also cumbersome: by integrating them here, any change to user branches is tested as part of the standard image building pipeline.