Set default grub output console to be text based

[schaefi]

Problem description

grub has changed its default console setting to be text based and no longer graphics based (gfxterm). This default setting actually makes more sense and is more generic applicable than the graphics console setting which we have now. Beginning with kiwi v10 such a change becomes possible and should be imho done

Impact

Users of kiwi will get the default text console instead of the graphics console if there is no console setting in the image
description. The setup for output and input console might be required for the expected result. e.g output=gfxterm
and input=console would be configured as:

<bootloader name="grub2" console="gfxterm console"/>

[Conan-Kudo]

We should probably give a heads-up to the maintainers of the SUSE/openSUSE images that they will need to specify gfxterm if they want that when we submit kiwi 10 to Factory.