Split randomizer mod into submodule

Co-authored-by: TakaRikka <takarikka@outlook.com>
Co-authored-by: gymnast86 <stock.joann@gmail.com>

include/Z2AudioLib/Z2SceneMgr.h

@@ -47,7 +47,7 @@ public:
     s32 getBgmLoadStatus(u32 wave) { return getWaveLoadStatus(wave, 1); }
     u8 getDemoSeWaveNum() { return loadedDemoWave; }
 
-private:
+// private:
     /* 0x00 */ JAISoundID BGM_ID;
     /* 0x04 */ int sceneNum;
     /* 0x08 */ int timer;