Today, apps rely on AppState and GlobalState in the ui/state_management module to deal with internal (app) and shared (global) state. These classes give apps an ability to read/write state, when is then synced to the URL as well as sessionStorage. They also react to changes in the URL and automatically update state & emit events when changes occur.
This PR introduces new state synching utilities, which together with state containers src/plugins/kibana_utils/public/state_containers will be a replacement for AppState and GlobalState in New Platform.