Implement initial framework for Dolphin importer

- Uses cache reading code from Lutris by strycore. https://github.com/lutris/lutris/blob/master/lutris/util/dolphin/cache_reader.py#L23

src/main.py

@@ -35,6 +35,7 @@ from src.details_window import DetailsWindow
 from src.game import Game
 from src.importer.importer import Importer
 from src.importer.sources.bottles_source import BottlesSource
+from src.importer.sources.dolphin_source import DolphinSource
 from src.importer.sources.flatpak_source import FlatpakSource
 from src.importer.sources.heroic_source import HeroicSource
 from src.importer.sources.itch_source import ItchSource
@@ -230,6 +231,9 @@ class CartridgesApplication(Adw.Application):
         if shared.schema.get_boolean("bottles"):
             importer.add_source(BottlesSource())
 
+        if shared.schema.get_boolean("dolphin"):
+            importer.add_source(DolphinSource())
+
         if shared.schema.get_boolean("flatpak"):
             importer.add_source(FlatpakSource())