devel/muon: update to 0.5.0

To keep the dependency chain as minimal as possible (in particular in
order to be able to use muon where we could end up with a circular
dependency when using meson), the manpage are now installed directly
generated from the distfile provided by upstream instead of generating
them with scdoc which itself depends on gmake and we use samurai instead
of ninja.

Keep pkgconf dependency, as pkgconf itself does not have a big
dependency chain and muon is faster when directly using libpkgconf.

Based on an inial proposal from diizy@

PR: 290759