drs: rgb camera hook (#524)

## Link to GitHub Issue, if one exists
n/a

## Description of change
Add plug&play hooks for RGB camera in DRS.

## Testing
Seems to work with my crappy Logitech C270

Camera options (brightness etc) seem to work in test menu as well).

Tested by another user with realsense camera + logitech camera, both
cams were detected correctly.

src/spice2x/launcher/options.h

@@ -236,6 +236,7 @@ namespace launcher {
             spice2x_IIDXWindowedTDJ,
             spice2x_DRSDisableTouch,
             spice2x_DRSTransposeTouch,
+            DRSRGBCameraHook,
             spice2x_IIDXNativeTouch,
             spice2x_IIDXNoSub,
             spice2x_IIDXEmulateSubscreenKeypadTouch,