docs/ci: document how to run traces locally
Basic documentation how to work with traces locally. More details can be found in the links to the Apitrace or Piglit suite.
How it does look: https://mesa.pages.freedesktop.org/-/mesa/-/jobs/25144429/artifacts/public/ci/local-traces.html
Reference: https://paste.sr.ht/~okias/c2101a3f561e7c7d01897054098b1b69d5e85fcc