[feat] Add a random hardware interface

[hgruniaux]

The Raspberry PI firmware has support for random hardware. Is not cool to be able to generate TRUE random from our own OS ? Of course, it is.

Tutorial: /~https://github.com/bztsrc/raspi3-tutorial/tree/master/06_random

POSIX compatibility:

• The file /dev/random: generate as much random bytes as read, blocking if there is not enough entropy
• The file /dev/urandom: generate as much random bytes as read, never blocking

LINUX compatibility:

• The system call getrandom() (see https://man7.org/linux/man-pages/man2/getrandom.2.html)