add WlOutput and OutputInfo getters

[Faervan]

I was unable to find any functionality to obtain the WlOutput that can be passed the the IcedOutput enum, so I added a command for it and an example as well.
Please let me know if merging this would be desired, and if anything should be changed before that. This is my first pull to another repository, please bear with me :)

[wash2]

Typically wayland specific libcosmic apps will use https://pop-os.github.io/libcosmic/cosmic/iced/advanced/graphics/futures/event/fn.listen_with.html and check for https://pop-os.github.io/libcosmic/cosmic/iced_winit/graphics/core/event/enum.PlatformSpecific.html PlatformSpecific::Wayland(wayland::Event::Output(output_event, wl_output)) events to be notified of output creation, updates, and removals. I'm not too opposed to getters, but I figure maybe it's best to keep track of the events. Does that sound ok for your use case?

[Faervan]

https://pop-os.github.io/libcosmic/cosmic/iced/advanced/graphics/futures/event/fn.listen_with.html

Oh no, missed that one :/
Well, that sure seems to work out as well... I think I might have overseen it because the online docs are build without the wayland flag so the PlatformSpecific event doesn't contain anything.
Well then you can close this if you don't think this is useful enough...

Thanks for your reply!