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/launcher.cpp

@@ -1118,6 +1118,9 @@ int main_implementation(int argc, char *argv[]) {
     if (options[launcher::Options::spice2x_DRSTransposeTouch].value_bool()) {
         games::drs::TRANSPOSE_TOUCH = true;
     }
+    if (options[launcher::Options::DRSRGBCameraHook].value_bool()) {
+        games::drs::RGB_CAMERA_HOOK = true;
+    }
     if (options[launcher::Options::spice2x_AutoCard].is_active()) {
         const auto text = options[launcher::Options::spice2x_AutoCard].value_text();
         if (text == "p1") {