GeophysicalModelGenerator Alpine test files

These are test files to be used with the GeophysicalModelGenerator.jl, to show its functionality.

The files are:

1. A 3D P-wave tomographic model of the Alpine region as described in a paper by Paffrath et al. 2021, which can be downloaded here. The data was converted into the GeophysicalModelGenerator GeoData format.
2. Topography model of the whole Alpine region, retrieved using GMT.jl and converted to GeoData
3. PNG cutout of the geological map of the Jura mountains from the PhD thesis of Schori, available here 
4. Basement topography of the Jura as GeoTIFF file, taken from Schori's PhD thesis, as uploaded here
5. A cross-section through the northern Jura from the same PhD thesis (provided as PNG)
6. Earthquake data from the 2021 La Palma eruptions, downloaded here in ASCII format