Fixup broken links, add warnings

[NeilHanlon]

Signed-off-by: Neil Hanlon neil@rockylinux.org

Author checklist (Completed by original Author)

• Contribution a good fit for the Rocky project? Title and Author MetaTags inserted ?
• Is this a non-English contribution?
• If applicable, steps and instructions have been tested to work on a real system
• Did you perform an initial self-review to fix basic typos and grammatical correctness

Rocky Documentation checklist (Completed by Rocky team)

• 1st Pass (Check that document is good fit for project and author checklist completed)
• 2nd Pass (Technical Review - check for technical correctness)
• 3rd Pass (Basic Editorial Review)
• 4th Pass (Detailed Editorial Review and Peer Review)
• Final pass/approval (Final Review)

[github-actions]

Test results for cbf0e89:

Number of broken URLs: 9

URL,RESULT,FILENAME
 https://github.com/rocky-linux/checksums,failed,release_notes/9_0.md
 https://cyber.gov.au/,failed,books/disa_stig/disa_stig_part2.md
 https://rundeck.rockylinux.org/api/11/storage/keys/ansible/vault,failed,books/learning_ansible/08-management-server-optimizations.md
 http://mirror.netweaver.uk/rocky/8.5/PowerTools/aarch64/os/,failed,books/admin_guide/13-softwares.md
 http://10.1.1.160,failed,guides/containers/podman-nextcloud.md
 http://wiki-doc/install.php,failed,guides/cms/dokuwiki_server.md
 http://10.56.233.189:8000,failed,guides/contribute/mkdocs_lsyncd.md
 https://www.breakingpitt.es,failed,guides/contribute/README.md
 https://manickathan.ch/,failed,guides/contribute/README.md

[sspencerwire]

Thanks @NeilHanlon