revision - 'lab5-networking' and 'lab6-user_and_group_management'

[ambaradan]

• moved 'main title' to frontmatter
• fixed the structure of the headers
• added inline codes and italics for paths and file names where missing
• added some additional descriptions for the exercise commands

Author checklist (Completed by original Author)

• Good fit for the Rocky Linux project? Title and Author Metatags inserted ?
• If applicable, steps and instructions have been tested to work
• Initial self-review to fix basic typos and grammar completed

Rocky Documentation checklist (Completed by Rocky team)

• 1st Pass (Document is good fit for project and author checklist completed)
• 2nd Pass (Technical Review - check for technical correctness)
• 3rd Pass (Detailed Editorial Review and Peer Review)
• Final approval (Final Review)

[github-actions]

Test results for 63f4af6:

Number of broken URLs: 5

URL,RESULT,FILENAME
 https://ftp.gnu.org/gnu/hello/hello-2.12.tar.gz,failed,labs/systems_administration_I/lab7-software_management.md
 http://your_ip,failed,guides/cms/mediawiki.md
 https://accel-ppp.org/,failed,guides/network/accel-ppp_pppoe_server.md
 http://$(hostname):8080,failed,guides/repositories/pulp_fetch_upload.md
 http://howtotechwriting.com/,failed,guides/contribute/README.md