Merge force-text-mode-console into the bootloader script

52-force-text-mode-console, running after 51-bootloader, calls
grub2-mkconfig (on Ubuntu that will happen via the update-grub call).
This call will overwrite all the changes that 51-bootloader did to the
grub.cfg. By merging the 52-force-text-mode-console code into
51-bootloader we avoid that. This also means that 51-bootloader will now
call grub2-mkconfig regardless of whether there is already and existing
grub2 configuration or not (52-force-text-mode-console did that in the
past anyway).

Additionally this commit enables the force to textmode code for openSUSE
(was previously only working correctly for Ubuntu and Fedora).

Closes-Bug: #1260323
Change-Id: Ida8e1a69df22d41ad70eb7154707c50613b536a8