Implement ability to limit how many hops away we want to see the graph

**Is your feature request related to a problem? Please describe.**
In the Hamilton UI, with large DAGs can be overwhelming. One way to get over this, is to show less.

**Describe the solution you'd like**
1. It would be nice to limit what is shown, based on the number of hops away from the current node in question. One could then gradually expand this as needed.
2. Could also potentially start off with a very high level module view instead when a DAG is above a certain node count?

**Describe alternatives you've considered**
N/A

**Additional context**
Should be self-explanatory. Can use https://github.com/DAGWorks-Inc/hamilton/blob/main/examples/hamilton_ui/notebook.ipynb to work off of.