feat: dolphin IPL.bin paths, scraper dedup by (name, destination)

dolphin: gc-ntsc-12.bin mapped to dolphin-emu/Sys/GC/<region>/IPL.bin
ref: DolphinLibretro/Boot.cpp:72-73, CommonPaths.h:139
scraper EXTRA_SYSTEM_FILES dedup now by (name, destination) to allow
same source file at multiple destinations.
retroarch pack: 448 files, 0 missing.

platforms/retroarch.yml

@@ -1238,6 +1238,15 @@ systems:
       md5: db92574caab77a7ec99d4605fd6f2450
       crc32: ad1b7f16
       size: 2097152
+    - name: gc-ntsc-12.bin
+      destination: dolphin-emu/Sys/GC/USA/IPL.bin
+      required: false
+    - name: gc-pal-12.bin
+      destination: dolphin-emu/Sys/GC/EUR/IPL.bin
+      required: false
+    - name: gc-ntsc-12.bin
+      destination: dolphin-emu/Sys/GC/JAP/IPL.bin
+      required: false
     core: dolphin
     manufacturer: Nintendo
     docs: https://docs.libretro.com/library/dolphin/