Add IO functionality to import / export multilayer network data in various formats

[pitmonticone]

Add functionality to import / export multilayer network data in various formats.

[colltoaction]

Hi! I'm Martín and I'm a developer working in the HIF project, an effort to share hypergraphs across many libraries, developed by members of SimpleHypergraphs.jl, XGI and other established libraries. We are looking to expand the community actively reaching out to higher-order network analysis, topological deep learning, and applied category theory libraries.

I hope you consider checking our repository where we provide the specification of a standard JSON format. Adding to_hif and from_hif methods would give your library immediate access to many datasets, while also the ability to export your hypergraphs for use in other packages. There are so far 4 Python implementations, each one with its tutorial. I hope this standard will be a solid foundation for researchers to share datasets and algorithms.

Let me know what you think and any way I can help make this happen!