For very large graphs, offer DataExplorer view

[yGuy]

When you try to open a large graph, it can take a while until the graph displays. Depending on initial layout and styling, it might take too long and annoy you, when you opened the graph accidentally or not being aware of its size.

In these cases, we could present a (configurable?) warning to the user and offer to immediately open the graph in data explorer mode where there should be fewer issues when you incrementally show the graph.