Check for additional valid MIME types for zip files.

Wondered why my local transport packages aren't valid zip-files for MODx until I found out that Firefox is uploading them with MIME type 'application/x-zip-compressed'.
Ignore case on MIME type check
Check for additional valid MIME types for zip files during package upload

* origin/pr/11274:
  Ignore case on MIME type check
  Check for additional valid MIME types for zip files.