build: Replacing make by meson.

build: Replacing make by meson.

This involves replacing all Makefiles by meson.build files.
Also the top-level configure script now simply invokes meson.
The top-level Makefile is just a wrapper for meson. It supports
the following operations:

make
make test
make install
make clean    # Remove build artifacts but keep configuration
make purge    # Remove build artifacts and configuration

Based on Martin Belanger's libnvme work.

Signed-off-by: Daniel Wagner <dwagner@suse.de>