Add the udev-rules file from flashrom source to the out directory. The
file contains rules for programmers used by flashrom. Members of the
`flashrom` system group are allowed to access these devices.
Also, add a module for installing flashrom and adding flashrom to udev
packages. The module can be used by setting `programs.flashrom.enable`
to `true`.
Signed-off-by: Felix Singer <felixsinger@posteo.net>
