Fixes and improvements to the ltfs_ordered_copy tool

[asivery]

Summary of changes

This pull request includes following changes or fixes:

• Fix the ltfs_ordered_copy tool crashing due to comparing bytes with str.
• Add optional dependency on tqdm for nicer progress bars.

Description

The first fix was required for me to even use this tool under modern python and pyxattr.

I believe a better progress bar might be more useful when copying smaller amounts of larger files - as of right now, this utility only shows the number of the file that's being copied.

I also believe it might be worth documenting somewhere, that sometimes it's absolutely crucial to use this tool instead of the system-avaliable cp or rsync. Without it, my drive (SAS IBM LTO7-HH) kept thrashing and throwing IO errors. Also, since python2 reached EOL six years ago, I think it might be worth removing mentions of it from the README.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have confirmed my fix is effective or that my feature works