Previous commit was not based on master, retry. Removed broken tar cutter, double extensions are not possible in temp files. Added tar support. Fixed extension switch.

This patch was automatically generated as part of the following inspection:
https://scrutinizer-ci.com/g/owncloud/core/inspections/cdfecc4e-a37e-4233-8025-f0d7252a8720

Enabled analysis tools:
 - PHP Analyzer
 - JSHint
 - PHP Copy/Paste Detector
 - PHP PDepend

Issue #7111

Conflicts:
	lib/private/vcategories.php

On windows the wrong file will be required: lib/archive/tar.php and not Archive/Tar.php.

Best would be to rename the lib/archive/tar.php or put it into a different folder

also handles bz2/gz compression