Starting with PEP 621, `pyproject.toml` is the standard way of
specifying project metadata.
Also switch to using the version from `pyproject.toml` instead of having
a west.version python module. Adjust documentation for the same.
Update MAINTAINERS.rst to use build for dist building.
Signed-off-by: Ayush Singh <ayush@beagleboard.org>
Ayush Singh