dead_lang_strings: Deleted all unused lang string

dead_lang_strings: Deleted all unused lang string

langs_cleaner.sh and langs_cleaner_addon.sh has been used to search for unused strings in all CGIs,
   which has been deleted.

Count of all deleted lines per language:

581 	Lines has been deleted in     langs/de/cgi-bin/de.pl
625 	Lines has been deleted in     langs/en/cgi-bin/en.pl
516 	Lines has been deleted in     langs/es/cgi-bin/es.pl
524 	Lines has been deleted in     langs/fr/cgi-bin/fr.pl
602 	Lines has been deleted in     langs/it/cgi-bin/it.pl
592 	Lines has been deleted in     langs/nl/cgi-bin/nl.pl
523 	Lines has been deleted in     langs/pl/cgi-bin/pl.pl
519 	Lines has been deleted in     langs/ru/cgi-bin/ru.pl
616 	Lines has been deleted in     langs/tr/cgi-bin/tr.pl

5098 	Lines has been deleted in     total