Move the Hermes spack repo to the grc-repo

Currently we have duplicated spack scripts in hermes_shm and hermes repos.

We should remove these from this repo and add grc-repo as a submodule.

GRC REPO: https://github.com/grc-iit/grc-repo

Locate the duplicated Spack scripts in the hermes_shm and hermes repositories, then inspect the referenced grc-repo. Confirm which files should be removed and how the repository should include grc-repo as a submodule. Done means the duplicates are gone and the new submodule is configured correctly.

Written by the indexing model from the issue text.