Make a new wayland backend using smithay-client-toolkit

[DJMcNab]

Previous commit histories can be found in waylander and waylandest. Those histories were abandoned to rebase over #103, #104 and #105.

Works towards #28

Future work, which should probably be done before merge

• [ ] Input types (Mouse/Keyboard)

Other future work, which can be collaborated on once merged:

• [ ] Timers
• [ ] Proper invalidation
• [ ] Pop-up windows
• [ ] Solve client side decorations. Either API for it and require users to implement, or using a fallback, if can be made to work.
• [ ] Menus of all kinds - same as client side decorations
• [ ] Clipboard - our API is synchronous, but Wayland's is async
• [ ] Monitors - should access the OutputState, I think What do we actually use monitors for?
• [x] Text fields/compose
• [ ] Cursors
• [ ] XDG desktop portal (file open/save, etc.)
• [ ] Fractional scaling (needs changes in sctk)
• [ ] Work out how to customise the App ID