resources: Add resources to build a PARSEC image

The pre-built PARSEC disk image can be obtained here:
http://dist.gem5.org/images/x86/ubuntu-18-04/parsec

Change-Id: Ib50a3abe976b666a0ddfb4161fe424b5d3d94a0e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-resources/+/29752
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby R. Bruce <bbruce@ucdavis.edu>