Add remaining shape files

[antagomir]

At the moment eurostat package has only NUTS2013 regions implemented.

The NUTS2013 regions are missing the resolution 3:1. This could be added.

Also the other administrative boundaries from GISCO could be added.

[muuankarski]

Missing resolution 1:3 million added for get_eurostat_geodata() added here: https://github.com/rOpenGov/eurostat/commit/881cc6768efee9daa2c8bc77b6f16db4399bc449

Meaning all the following resolutions work now at differeent nuts levels (0,1,2,3)

library(eurostat)
get_eurostat_geospatial(resolution = "60", nuts_level = 0) %>% select("geo") %>% plot()
get_eurostat_geospatial(resolution = "20", nuts_level = 0) %>% select("geo") %>% plot()
get_eurostat_geospatial(resolution = "10", nuts_level = 0) %>% select("geo") %>% plot()
get_eurostat_geospatial(resolution = "3",  nuts_level = 0) %>% select("geo") %>% plot()
get_eurostat_geospatial(resolution = "1",  nuts_level = 0) %>% select("geo") %>% plot()