Replace load_{uni,bi}directional with Swh{Uni,Bi}directionalGraph::new

pyo3/src/lib.rs

rust/crash_course.md

rust/examples/bfs.rs

rust/examples/bfs_labels.rs

rust/examples/compare-graphs.rs

rust/src/arc_iterators.rs

rust/src/bin/swh-graph-grpc-serve.rs

rust/src/graph.rs

rust/src/properties/mod.rs

rust/tests/properties.rs

rust/tests/stdlib.rs

rust/tutorial.md

tools/contributions/src/bin/origin-contributors.rs

tools/file_names/src/bin/list-files-by-name.rs

tools/file_names/src/bin/popular-content-names.rs

tools/file_names/src/bin/popular-content-paths.rs

tools/provenance/src/bin/compute-directory-frontier.rs

tools/provenance/src/bin/compute-earliest-timestamps.rs

tools/provenance/src/bin/contents-in-directories.rs

...venance/src/bin/contents-in-revisions-without-frontier.rs