Refactor the m3ulcb machine templates

Refactor the m3ulcb machine templates

This splits the machine templates for the m3 into three:
- m3ulcb = plain m3ulcb with graphics driver package
- m3ulcb-nogfx = plain m3ulcb without graphics driver package
- m3ulcb-kf = m3ulcb with kingfisher baseboard and graphics driver package

This improves maintainability of the m3ulcb machine targets.

Bug-AGL: SPEC-3443

Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Change-Id: Ib878833709ddc7f706fd15107bfb8dee4272d431
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/24913
Reviewed-by: Stéphane Desneux <stephane.desneux@iot.bzh>