Fix GetDesiredLanguage and expose a way to set the desired language, default to english

Ryujinx.Core/OsHle/SystemLanguage.cs

@@ -0,0 +1,23 @@
+namespace Ryujinx.Core.OsHle
+{
+    public enum SystemLanguage
+    {
+        Japanese,
+        AmericanEnglish,
+        French,
+        German,
+        Italian,
+        Spanish,
+        Chinese,
+        Korean,
+        Dutch,
+        Portuguese,
+        Russian,
+        Taiwanese,
+        BritishEnglish,
+        CanadianFrench,
+        LatinAmericanSpanish,
+        SimplifiedChinese,
+        TraditionalChinese
+    }
+}