Implements proper save path (#386)

* initial save path implementation

* fix savedatatype offset, remove incomplete createsavedata implimentation

* address nits

* fix crash if npdm is not found

* made saveinfo readonly, other stuff

* remove context param from saveinfo contructor

* fix style

* remove whitespace

Ryujinx.HLE/HOS/Horizon.cs

@@ -109,7 +109,7 @@ namespace Ryujinx.HLE.HOS
                 }
             }
 
-            if (!MainProcess.MetaData.Is64Bits)
+            if (!(MainProcess.MetaData?.Is64Bits ?? true))
             {
                 throw new NotImplementedException("32-bit titles are unsupported!");
             }