Change how we calc backup exclusions list range

What does this MR do and why?

Fixes the way we iterate through and remove items in the backup exclusion list.

Previously we were iterating through a list. Now we are using a slice operator to recapture the list attributes every iteration (we get the updated length/order)

We would end up skipping items in the iteration of directories in this case. It was very random, but if you select about 3-7 directories to exclude you will more than likely not see all of them excluded.

This also adds better debug logging for backups as well as comments.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Have you checked this doesn't interfere/conflict/duplicate someone elses work?
• Have you fully tested your changes?
• Have you resolved any lint issues?
• Have you assigned a reviewer?
• Have you applied correct labels?