GitLab

Separate the instructions to clone the repostory with Git LFS into a
separate section, and add a section with some minimal instructions to
get started for buildnthg Chromebook firmware images.
Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>

Add a basic README.md with some minimal instructions about how to
flash a firmware image on a Chromebook using servoflash.py.
Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>