meson: install the configuration directories

meson: install the configuration directories

Install the /{etc,usr/lib}/{depmod,modprobe}.d/ configuration
directories as part of out install action.

Currently a handful of distros (Debian, Gentoo, Fedora, Arch) do that
manually, where we can have it in the upstream project instead.

As a pie in the sky idea, in the future we may choose to enforce
particular permissions, ownership, etc and this should make it a little
less fragile across the ecosystem.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/231
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>