docs(guide): add rockydocs tool guide

[wsoyinka]

This PR introduces the new rockydocs contributor tool/script. Useful for contributors and maintainers that want to quickly setup their local systems for contributing to the Rocky Docs project and mimic the exact look and feel of the main docs website - https://docs.rockylinux.org - on their local system.. rockdocs.sh is a Rocky Linux Documentation - Contributor Script

[github-actions]

Test results for 524be04:

Number of broken URLs: 4

URL,RESULT,FILENAME
 https://ftp.gnu.org/gnu/hello/hello-2.12.tar.gz,failed,labs/systems_administration_I/lab7-software_management.md
 http://$(hostname):8080,failed,guides/repositories/pulp_fetch_upload.md
 http://your_ip,failed,guides/cms/mediawiki.md
 https://repocompare.rockylinux.org,failed,release_notes/8_5.md