v1.5-beta: setup assistant needs a little formating improvement

[interduo]

I've cleaned a lot postinst in deb package. But rust LibreQoS setup assistant needs a little work also:

Now it looks:

If files are skipped it looks unificated:

Small things:

• no spaces between filenames and msg,
• different colors in messages red color,
• message format differs oneline/two lines (suggest using unificated format),
• remove "Don't forget to add some users" (its doubled)