Update ArcGIS data link to https

[cwhite911]

Change location of ArcGIS assignment data or serve over https from fatra. Browsers will give security warnings preventing the download of data over http.

http://fatra.cnr.ncsu.edu/geospatial-modeling-course/data/gdbs.zip

[wenzeslaus]

Some time ago, we started to move away from custom hosting and use Zenodo. The DOI is often useful anyway (maybe not here). The download experience might be worse, though.