package/dust: new package

dust is an alternative of the command du from the Linux kernel,
written in Rust. It aims to be more intuitive and visual in order
to give the user a better view of his system's storage capacity.

Signed-off-by: Nicolas Tran <nicolas.tran@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>