[Open Assets] Super Mario Kart Pack v1.2

Changelog:
-Fixes an issue on koopa beach caused by the scaling
-More Rings on Rainbow Road

Changelog :
- Reduced the size of every map aviable in multiplayer by 25% following a complain about them being too small.
- Changed the battle course music.

Spoiler: Spoiler for GP content: changes

- increased the size of "Sealed Star Slide".
- Added the component to trigger the sky and music changes in sealed stars.
- Garden and Block had their aestetics altered, but dont suffer any layout changes, the modifications being purely visual.
- Broken Spectrum didn't change a bit.