New tutorial walking through the ways data gets into a GRASS project, organized by
import method:

1. Import a file — r.import / v.import
2. Link, then reproject — r.external in a staging project + r.proj
3. Add-ons that fetch data — r.in.usgs, v.in.ags, r.in.ssurgo
4. Python packages and plain APIs — pygris, STAC/Planetary Computer, requests

The running example is the recipe used to build the new North Carolina sample dataset
for Raleigh, so it doubles as a template for assembling an equivalent dataset for
another area. Closes with metadata and styling (r.support, r.category, r.colors,
semantic labels) and a table of sources and terms of use.

Adds content/tutorials/import_data/: the .qmd, 10 webp figures, and the original
dataset notebook (linked via code-links).