freedreno: add CI for envytools tools

This also tunes `.freedreno-rules` a bit so that it isn't triggered by
various tools that don't effect the driver build.

The .gitlab-ci directory is kept separate from the toplevel one so that
updates to (for example) reference decode output do not trigger all the
other-driver jobs to run.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6070>
16 files changed