Make map hierarchical

[nCov19-DataPoints]

• Add complete world map using JHU data.

• Use more detailed data where available.

• Use topojson insteead of geojson for the necessary map

• What to do if the detailed data is only available for some parts and not at all for other?

• What to do if the data for the parts is older/newer than the data for the whole?

• What to do if the data for the parts is inconsistent with the data for the whole?

• First solution: ignore any inconsistencies, display all detailed data which is available on top of the summary data (or better: use the summary data to fill out all the missing parts of the more detailed data).