Draft: wayland: drm-lease: add new vout window module for exclusive access

The DRM lease wayland implementation is using the drm-lease-v1 protocol to acquire a DRM lease including a given connector, mainly for VR headset since compositor might not expose the other screens that way currently, and use it as a fully exclusive DRM output.

This is still WIP since it depends on !893 (merged) being merged for the vout_window handle/display interface, and though it's a separate issue, the display still has issues with retrieving a plane from the DRM lease, so is not able to display anything.

The priority will need tweaking, and it might also lack a vout_window_cfg_t item to ensure this module is only enabled when exclusive access to display is requested, be it by whitelisting exclusive access in this module, blacklisting exclusive access in the others or creating a separate vout window capability for exclusive access (given that X11 and vulkan also has this).

I hope this module can comfort others in how the handle/display values for KMS are chosen.