build: Port to meson
Depends on:
- !59 (merged) (for gettext migration) - included here
- xfce/xfce4-dev-tools!98 (merged) (for CI, xfce-do-release, etc)
(Do we have plans for releasing additional 4.18.x releases from master
branch? To preserve distutils-extra build I guess can investigate combination of meson + intltool like this)