Preserve reciprocal edges in the NetworkX dialect

[j6k4m8]

Closes #44

• use NetworkX OutEdgeView for directed backends and EdgeView for undirected backends
• preserve reciprocal directed edges in iteration, calls, and metadata lookup
• add regression coverage for both directions

Also I love that #88 closes #44, that feels somehow very good to me. Unfortunately #22 and #11 are totally unrelated.

[codspeed-hq]

Merging this PR will not alter performance

✅ 17 untouched benchmarks

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_{Comparing fix/networkx-directed-edges-44 (97d793c) with master (f322db8)}