Do not re-render everything on any property change

[bprusinowski]

Currently, we use one huge useReducer to keep track of the configurator state. Due to this design, the whole application re-renders on every keystroke when adding a chart title, for example (or really, changing any other property).

While it's not terribly slow, the lag is clearly noticeable, especially when developing the application. We should potentially split up the one big reducer into several, dedicated ones that would only make the affected parts of the app re-render.

[ptbrowne]

Another things that could help would be to use selectors (https://redux.js.org/usage/deriving-data-selectors#basic-selector-concepts) instead of always asking for the whole state. components would wake up less as they would not be woken up if the area of the config they are concerned about has not changed.