Add more local data sources

[boogheta]

Ideally a CSV file for a country with each row having at least a date, a region, and a list of cases numbers.

Possible sources:

• https://coronavirustechhandbook.com/data

• https://github.com/covid19-eu-zh/covid19-eu-data

• https://covid19-eu-data-cache.now.sh

• South Korea ?

• Iran ?

• Netherlands ?

• Sweden ?