New function: read_habitatmap_terr()

[florisvdh]

Practical steps: install n2khab from this branch (read_habitatmap_terr) if you're to test the new function (and its documentation). To be working out-of-the box (without customized arguments), it needs the habitatmap_terr.gpkg file in your local folder n2khab/20_processed/habitatmap_terr, which is in the Q-drive location (under 20_processed).

• Note: the Zenodo-link in the function's documentation is not yet implemented (habitatmap_terr is still to be uploaded)
• Git note: this branch builds on top of branch read_sf while the PR is directly to master. What actually matters here is commit fe2622d -- as long as read_sf isn't merged (PR #27), the earlier commits below are those of branch read_sf _(I didn't use that one as reference for the PR though, as read_sf will probably be merged into master first and then the current PR would complain and close)_

[florisvdh]

@w-jan @ToonHub Any remaining comments regarding commit fe2622d?