Add documentation to point to the requirements repository
and give the contributors a guideline how to add requirements
to that repository.
Signed-off-by: Simon Hein <Shein@baumer.com>
Add the safety documentation to the Zephyr documentation tree.
Starts with the safety overview which describes the general goals
for the safety in zephyr and introduces a process overview how a safety
certification can be achieved in the zephyr project.
Signed-off-by: Simon Hein <Shein@baumer.com>