Update page: Backing Up Your WordPress Files

[javiercasares]

File: security/backup-files.md

This page needs a general review and update.

IMPORTANT: there are two subpages for security/backup.md and security/backup-database.md, so this need to be check and refer those pages when needed.

If you add documentation from another WordPress.org page, indicate it in the Changelog or in the comments of this issue.

To-Do

• General review and updating

[javiercasares]

Please be aware, #148 #149 #150 are related.