* module_utils.urls: add fetch_file function
* apt: use fetch_file instead of own download()
* unarchive: use fetch_file instead of own codecopy
* apt: add test for deb=http://…
* unarchive: add test for a remote file download and unarchive
* yum: replace fetch_rpm_from_url by fetch_file
* use NamedTemporaryFile
* don't add a dot to fileext, it's already there