website: Update the gem5art tutorial for v21.2

This is not complete, the gem5art tutorial still reference configs
and resources which has since changed. This should be updated completed
ASAP.

Change-Id: Ia1b07d76fb1e976b6f5dafda3c93b3c2837180c4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/54726
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby Bruce <bbruce@ucdavis.edu>
3 files changed