Rename Edge to Link

[evetion]

everywhere

This is automatic rename, and then slowly staging the changes. Main exceptions found so far:

• UGrid uses edge_dimension and similar names
• Networkx has a Graph edges attribute and methods
• Graphs.jl has an edges method and keywords

@visr The only breaking change are that output arrow tables now have link_id instead of edge_id. I don't think there's a way around that.

[visr]

This is pushing the link. An edge to the past.