[RAPPS] Introduce 'SizeBytes' DB entry and use it for display

This will allow us to reduce the DB size a little by avoiding
duplication for each and every entry.
Original patch by JIRA user "swyter"

CORE-10310

base/applications/rapps/include/available.h

@@ -75,6 +75,7 @@ private:
     VOID RetrieveInstalledVersion();
     VOID RetrieveLanguages();
     VOID RetrieveLicenseType();
+    VOID RetrieveSize();
     inline BOOL FindInLanguages(LCID what) const;
 };