ci: Uprev Mesa

This is a manual attempt to uprev Mesa in Virglrenderer because changes in Mesa require changes in Virglrenderer that ci-uprev cannot manage to make.

The variable MESA_BASE_TAG definition has been moved to the job definition as it has different values depending on the configuration.

To help in the organization of jobs relation, a new hidden job called .use-build-image holds the configuration for the build jobs like the .use-{gl,vk}-test-image does for the two groups of test jobs.

Those two .use-{gl,vk}-test-image now define the MESA_BASE_TAG specifically for those jobs.

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By the way, by the time I'm preparing this merge request as a draft, some jobs are facing problems that seem different from expectations (See pipeline 941407).

• The jobs in the set piglit-{gl,gles}-virt also show a problem completing the task.
• The job venus-lavapipe has a problem I am trying to solve. It takes too much time, and the job timeout before completing the task.