Add some sort of features to handle graphs with a large number of edges

[bskinn]

Mermaid now has a configurable cap on the max number of edges in a graph: mermaid-js/mermaid#5086

Uncertain at this time what the cap is on GitHub (at least 676 edges as of last testing), which is where we'd expect a lot of these diagrams to be shown.

We may need to implement some manner of reporting of edge counts, at minimum... or perhaps some sort of auto-diagram-splitting to keep each diagram under a given edge threshold?