librem5-flash-image: Add option to setup udev rule
As seen in
developer.puri.sm!425 (diffs, comment 137956)
we could use uuu
to setup necessary permissions to flash images but they are too broad (https://github.com/NXPmicro/mfgtools/pull/248) so we should add an option to librem5-flash-image
that does the equivalent.