Add Case-Insensitive Field to Phrases table for storing Labels

Need to add new Case insensitive column to Phrases table for 2 cases:

1. Language Pack Upgrade fails since we can't properly compare all NEW phrases when Label cases doesn't match.

2. MySQL INDEX is not working when any operation as done with the Field in WHERE clause. By adding a separate field we guarantee that Field will be selected using INDEX and will improve loading time.