dir: Add support for X-Flatpak-RunOptions in exported desktop files
dir: Add support for X-Flatpak-RunOptions in exported desktop files

A desktop file can specify this key to add additional arguments
to flatpak run. Right now, only 'no-a11y-bus' is supported.

Closes: #1579
Approved by: alexlarsson

matthiasclasen/flatpak,flatpak/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,matthiasclasen/flatpak