[RAPPS] Replace Extract with FDI for handling .cab

FDI allows to have user-defined callbacks for file handling.
Since it doesn't provide support for Unicode we convert strings to
multi-byte UTF-8 and handle them appropriately in the callbacks. They
are properly null-terminated so FDI won't choke when doing operations
with strings.

Thanks to hbelusca and mjansen for the help.

CORE-14466

base/applications/rapps/include/available.h

@@ -86,6 +86,8 @@ struct AvailableStrings
     ATL::CStringW szCabPath;
     ATL::CStringW szAppsPath;
     ATL::CStringW szSearchPath;
+    ATL::CStringW szCabName;
+    ATL::CStringW szCabDir;
 
     AvailableStrings();
 };