Refactor kms_vaapi and kms_cuda

Also fixes color metadata, color range and hdr on nvidia wayland.

include/capture/kms_vaapi.h

@@ -12,7 +12,6 @@ typedef struct {
     gsr_egl *egl;
     const char *display_to_capture; /* if this is "screen", then the first monitor is captured. A copy is made of this */
     gsr_gpu_info gpu_inf;
-    bool wayland;
     bool hdr;
     gsr_color_range color_range;
 } gsr_capture_kms_vaapi_params;