Updates for version 10 for sftp.md

[sspencerwire]

• remove incorrect level 1 heading (pulling from meta)
• add sub-heading
• remove notes specific to RL 8 and 9
• fix some markdown errors in original file
• replace "we" and "our" with "you" and "your" throughout
• some sentence simplification

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 44b9df4:

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