feat(library): Steam wishlist tab with prices and discounts

The library page gets a Bibliothek | Wunschliste tab bar. The wishlist shows
the current store price, the discount and can show only games on sale.

public/i18n/de.json

@@ -207,5 +207,14 @@
       "MEDIUM": "Mittel",
       "LOW": "Niedrig"
     }
+  },
+  "WISHLIST": {
+    "TITLE": "Wunschliste",
+    "ONLY_ON_SALE": "Nur im Angebot",
+    "EMPTY": "Deine Steam-Wunschliste ist leer oder privat. Stelle sie in Steam auf öffentlich; der nächste Sync holt sie.",
+    "NONE_ON_SALE": "Gerade ist nichts von deiner Wunschliste im Angebot.",
+    "NO_PRICE": "Noch kein Preis",
+    "ADDED": "Hinzugefügt am {{date}}",
+    "ERROR_LOAD": "Wunschliste konnte nicht geladen werden."
   }
 }

public/i18n/en.json

@@ -207,5 +207,14 @@
       "MEDIUM": "Medium",
       "LOW": "Low"
     }
+  },
+  "WISHLIST": {
+    "TITLE": "Wishlist",
+    "ONLY_ON_SALE": "On sale only",
+    "EMPTY": "Your Steam wishlist is empty or private. Make it public in Steam; the next sync fetches it.",
+    "NONE_ON_SALE": "Nothing on your wishlist is on sale right now.",
+    "NO_PRICE": "No price yet",
+    "ADDED": "Added {{date}}",
+    "ERROR_LOAD": "Could not load the wishlist."
   }
 }