Replace GLFW with a custom Wayland client

[stuarthayhurst]

Target only Wayland, drop X11 support

• Support various protocols:
  • Look into toplevel_icon protocol for window icons
  • Look into color_management protocol for HDR and colour management
  • Look into linux-drm-syncobj protocol for explicit sync
• Rework input system to skip intermediate steps and trackers
  • Provide enums for keys
  • Allow multiple keys to change per poll
• Provide more control over context creation / graphics API initialisation
• Provide more control over framebuffer creation
• Provide more control over refresh rate
  • Includes vsync and VRR support, on a per-frame basis
• Provide control over initial window position and mode
• Use libdecor for window decorations
• Required features:
  • Icons
  • Title bar
  • Window controls
  • Window resizing
  • Window mode (windowed, fullscreen, borderless)
  • Input modes (raw mouse movement / deltas, key input modes)

It might be work building this as a sub-project, as this doesn't need to be engine specific.

This is probably a little over-ambitious, but this issue serves as a place to collect my thoughts on it.