A vulkan renderer has been added to wlroots. Vulkan support is not ready for panfrost yet,
but it is at least buildable and other platforms may benefit from it.
Adjust the Recipe to automatically build the renderer if vulkan is in DISTRO_FEATURES.
Sways default config makes use of swaybg. Add it as RDEPEND and install default
wallpapers. Most people will expect to have a way to use wallpapers so in order
not to configure things to death this feels like a sane default setting.
