Store improvements

- Store games by source
- Added convenience dunder methods (contains, iter, len, getitem)
- Added store.get
- Changed `enable_in_pipeline` for `toggle_in_pipeline`

src/details_window.py

@@ -155,9 +155,10 @@ class DetailsWindow(Adw.Window):
                 return
 
             # Increment the number after the game id (eg. imported_1, imported_2)
+            source_id = "imported"
             numbers = [0]
             game_id: str
-            for game_id in shared.store.games:
+            for game_id in shared.source_games[source_id]:
                 prefix = "imported_"
                 if not game_id.startswith(prefix):
                     continue
@@ -168,7 +169,7 @@ class DetailsWindow(Adw.Window):
                 {
                     "game_id": f"imported_{game_number}",
                     "hidden": False,
-                    "source": "imported",
+                    "source": source_id,
                     "added": int(time()),
                 }
             )