python 3 is default now, in all the distros

specifically calling "python3" often doesn't work anymore

python2 is obsolete

let python2 die

the deleted patch (in this commit) was written to fix an
issue theoretically; it hasn't been fully tested, and some
people have reported strange issues since this patch was
merged - there is no proof that this patch causes them, but
removing this patch is the correct thing to do regardless

This reverts commit 1497ae045104145de677fd151da4de6e92be4e5a.

The blanket GRUB patch seems to break PS/2 keyboard handling across
other platforms, so revert it.

This introduces a patch to grub which disables the coreboot
specific handling, allowing PS/2 keyboards to be handled the
same as i386-pc.  However this alone breaks the keyboard in
Linux, requiring coreboot to perform PS/2 initialization.

I think GRUB may be restoring the original configuration of
the PS/2 controller once it exits, and if coreboot doesn't
initialize the controller then it's restored to the default
state which Linux doesn't seem to like. I think the emulated
keyboard interface provided by the EC on the E6400 behaves
in a non-standard way that is incompatible with the old
coreboot specific handling.

gnulib too

gnulib...

with this change, it's unlikely we'll hit errors again. previously,
some projects used were calling "python" which in context was
python3, but on some setups, the user only has python2 and python3
but no symlink for "python" (which if exists, we assumed linked to
python3)

now it's unambiguous. docs/build/ can probably be updated now, as
a result of this change, to remove the advice about that

mitigate missing characters in unifont for border/arrow characters. this saves
space because now it is no longer necessary to add a custom font

the background added has the libreboot logo on it, and it's 10kb in size unlike
the old gnulove background that was hundreds of KB