Clean non-code content from repo

In extension to PR #21 :

Suggestion to move

- https://github.com/csc-training/geocomputing/blob/master/routing.md to tutorials in docs (no code)
- https://github.com/csc-training/geocomputing/blob/master/NLS_geopackage_tests.md to env-guid or Paituli or docs data page ? (no code)