Issue for tracking technical decisions and progress.

To accomplish #756 and connected issues, we need first to pull top-panel into visualisation itself. To do this, we need to clean up code around BaseVisualization.

1. First step is to remove BaseVisualization as a base class. Composition, not encapsulation

• Remove scroll state from BaseVisualization. Different visualisations use scroll differently and they should be responsible to track this. For example Table is not interested in horizontal scroll at all. Move scroll state to specific visualisations #775
• Remove dragOnSeries from state. It is not used. Remove old and unused code #776
• Create component for managing highlight. It would keep Highlight state and provide useful callbacks/getters HighlightController #777
• Extract data fetching into separate component. Visualisation can provide query function and/or shouldRefetchData predicate. Component will render error and loading states and provide to visualisation data as props iff in loaded state. DataProvider #779

2. We need to clean up components in top-panel.

• Remove references to Components. All communication should be done through props and/or state. "Dirty" tiles should be added to Essence. It is ephemeral state, not persisted into url/view definition and can be reset when reconstructing Essence Partial Tiles #780

3. All generic solution will be encapsulated in CenterPanel component with following props:

• visualisation - Component for rendering chart. Get's few props like data, highlight etc.
• topMenu - Component for rendering top menu - splits, filters etc.
• shouldFetchData - predicate for deciding if props change constitute data refetch. Optional.
• makeQuery - function that creates Plywood query from Essence. Optional.

4. All Visualizations will use CenterPanel component and provide props. For LineChart I imagine something like this:

function LineChartVisualization() {
  return <CenterPanel
   visualisation={LineChart}
   topMenu={LineChartTopMenu} 
  shouldFetchData={Essence.equals}
  />;
}

Because JSX invocation can also take render prop, we are free to customise existing components even if signature does not fit, like visualisation={({data, highlight}) => <LineChart series={data[0]} hasHighlight={highlight.hasHighlight()} changeHighlight={highlight.setNewHighlight} />