consider new structure for spaghetti

[jGaboardi]

May consider new structure for .py files and import in the repo...

- spaghetti
        | - network.py
        | - analysis.py
        | - connectivity.py -- connectivity stats
        | - network_voronoi.py -- network-constrained voronoi diagrams
        | - XX util.py -- break into seperate files (below)
        | - allocate.py -- snapping --> singular/multiple, pp2n, etc.
        | - shortest_path.py -- tree generation + dijkstra/(maybe A*)?
        | - plus.py -- "plus" functionality including geopandas stuff

related: #76, #126 , #195, #373, #392

Also: Refactor:-spaghetti-v2.0

[jGaboardi]

At over 3000 lines, network.py is getting a bit unwieldy and would benefit from putting more utility-type functionality in a separate file.

Some ideas:

• _network.py
• net_utils.py
• build.py
• builder.py
• netbuilder.py

[jGaboardi]

Now there are 3 functions for extraction/creation in network.py:

• extract_components()
• element_as_gdf()
• regular_lattice()

Maybe move these into a separate file --> features.py