[feat] [streams]: update StockMap and UserInfo streams for new updates in GameState stream

[Sudhindra3000]

Features:

• Used the stream controller pattern(ex: UserInfoGenerator) to update stock map stream

  • Previously we used CombineLatestStream from rxdart.
  • But for it to work properly all the source streams need to have an initial value. Because the resultant stream won't emit anything until all sources emit atleast one value
  • GameState stream cannot have an initial value. So there's no way to use CombineLatestStream anymore

• Some other minor refactorings done in stream transformations

Todo:

• Create a stream for isMaketOpen
• Show notifications for some updates in game state