Web support

[bdlukaa]

Add web support for the package.

• Block RTSP source on the web
  RTSP streams are not available in most of browsers. Only HLS and MJPEG should be options, which HLS being the default.
• Block dart:io:Platform calls. TargetPlatform and kIsWeb should be used instead.
• Implement routes and url options
  • Use go_router to make routing and sub-routing.
  • Implement url options, such as hiding the navigator tray and other app settings.
    This is useful specially for embedding the website and viewing a specific screen, for example.
• File handling
  Web doesn't support i/o operations, and handling files as file entities is not possible. Use bytes whenever possible.