tests/vm: fedora autoinstall, using serial console

tests/vm: fedora autoinstall, using serial console

Download the install iso and prepare the image locally.  Install to
disk, using the serial console.  Create qemu user, configure ssh login.
Install packages needed for qemu builds.

Yes, we have docker images for fedora.  But for trouble-shooting it
might be helpful to have a vm too.  When vm builds fail you can use
it to figure whenever the vm setup or the guest os is the problem.

Signed-off-by: Gerd Hoffmann <[email protected]>
Tested-by: Thomas Huth <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Tested-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <20190617043858[email protected]>
Signed-off-by: Alex Bennée <[email protected]>