Merge branch 'meshlib_tests' into 'main'

docs/examples/howto_meshlib/plot_meshlib_vtu_input.py

ogstools/definitions.py

ogstools/meshlib/boundary_subset.py

ogstools/meshlib/tests/__init__.py

tests/data/meshlib/compose_geomodel/layersets.csv

tests/data/meshlib/compose_geomodel/materialset.csv

tests/data/meshlib/mesh1/set1.csv

tests/data/meshlib/mesh1/surface_data/00_KB.vtu

tests/data/meshlib/mesh1/surface_data/01_q.vtu

tests/data/meshlib/mesh1/surface_data/02_krl.vtu

tests/data/meshlib/mesh1/surface_data/03_S3.vtu

tests/data/meshlib/mesh1/surface_data/04_krp.vtu

tests/meshlib/__init__.py

tests/meshlib/test_demo.py

tests/meshlib/test_layer.py

tests/meshlib/test_layer_set.py

tests/meshlib/test_prism_mesh.py

tests/meshlib/test_read_xdmf.py

tests/meshlib/test_region.py

tests/meshlib/test_simplified_mesh.py