Filter based on name

It would be neat if you could filter based on name and have just those nodes (and maybe their dependencies/dependents) show up, or at least just those links at any length.

E.g. the `biojs-*` set of packages generally depend on one another for functionality, but they're fairly widely spread across the "galaxy", and thus hard to see relationships amongst them.

No implementation file or test is named in the issue. First locate the graph filtering and rendering entry points, then review how nodes, links, and package names are represented. Done means the intended name filter behavior is defined and the visualization shows the selected packages and any explicitly supported related items.

Written by the indexing model from the issue text.