Add Fedora distributions to test suite

[haxorof]

Currently no Fedora versions are tested automatically via test.sh because there has been an issue to do reliable tests using VirtualBox 5.2.18. Now VirtualBox 5.2.20 is available which fix issues which now make the vbguest plugin to work again as expected.

Containers for different Fedora versions are available and shall be included in vagrant_config.yml. Need to check if Vagrant boxes from Fedora can be used or use the images which are now commented out in the file.