Final Release of recommender applications.

Version1 (appserver.py is backend, load flutter with intellijidea, visual studio or on terminal of app directory execute -> "flutter run" (you might need to execute "flutter clean" first if you get an error.)
Version2 (appserver.py is backend, load flutter with intellijidea, visual studio or on terminal of app directory execute -> "flutter run" (you might need to execute "flutter clean" first if you get an error.)