meson: new package

This new package provides the host variant of the Meson Build System, an
open source build system meant to be both extremely fast, and as user
friendly as possible.

More precisely, Meson creates configuration files for the Ninja build
system.

Besides building Meson, it generates a configuration file
("$(HOST_DIR)/etc/meson/cross-compilation.conf") to be used when
cross-compiling a Meson-based project.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>