Non-existent files still linked for spack examples

[sevmag]

The FAS RC documentation still links this repo for examples of how to use spack (https://docs.rc.fas.harvard.edu/kb/spack/)

However all of the links are dead (404)

[paulasanematsu]

@sevmag Apologies for the broken links. All of the Spack examples were migrated to FASRC main documentation website https://docs.rc.fas.harvard.edu/kb/spack-package-manager/. We will fix the broken links.

[sevmag]

Thank you!