geodata and covid-19 should probably contain sample data

Both https://datahub.io/core/geodata and https://datahub.io/core/covid-19 will overhelm the browser resource usage and break the page, this is mainly due to the fact that both contain resources in the hundreds of megabytes, this could probably be fixed on covid-19 with sample data, however im not sure its possible to do that with geodata, since its mostly geojson.