rb: touch debug overlay, tweak scaling (#801)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change
Similar to #797, draw an overlay to debug touch issues for reflec beat.

For rb, we draw on the ImGui surface. Draw horizontal and vertical line
for triggered sensors, and also a bounding box if scaling is in use.

Make small tweaks to how scaling works.

## Testing
Verified volzza 2 / reflesia / 1st game (landscape KBR)

src/spice2x/CMakeLists.txt

@@ -432,6 +432,7 @@ set(SOURCE_FILES ${SOURCE_FILES}
         games/rb/rb.cpp
         games/rb/io.cpp
         games/rb/touch.cpp
+        games/rb/touch_debug.cpp
         games/bs/bs.cpp
         games/bs/io.cpp
         games/rf3d/rf3d.cpp