Improve comparison between files found via changes.csv and ROLIE feeds

[JanHoefelmeyer]

As mentioned in https://github.com/csaf-poc/csaf_distribution/pull/441#issuecomment-1691600300, a singular file can be linked to in different valid ways. Currently, the checker will treat a file found within the same place as two different files unless the string resulting from the expanded url from the changes.csv is exactly equal to the entry in the ROLIE feeds.

This needs to be fixed -> If changes.csv and ROLIE feeds are valid and point to the same file it must be valid regardless of the expansion.