Add dedicated SFTP Client documentation (that points out port 2022)

[Wavewash]

I was trying to connect to muos via a sftp client but found that the port wasn't the default 22. I found a helpful reddit post that pointed out the port needed to be 2022. The documentation doesn't seem to point out the port so I figured I could add it.

Reddit link: https://www.reddit.com/r/RG35XX_H/comments/1d0l6p0/comment/lsi3p38/

I didn't want to crowd the existing documentation page for SFTP + FileBrowser - but honestly this content could easily fit there too.

Changes in this PR:

• Created sftpclient.md under the Web Services category.
• Clearly defined the connection parameters (IP, Port, Username, Password).
• Highlighted Port 2022 as the mandatory port for successful connection.
• Maintained consistent styling and structure with the existing documentation.

Appreciate all your guys work. Thanks.