feature: explain - mark when dependency is bundled

[kumavis]

when using npm explain <package> its useful to see if the package has been bundled. this is especially useful when trying to understand the provenance of a package's content

it would additionally be helpful to indicate when an edge includes a dependency as bundled, but that will require a change in @npmcli/arborist's Edge.prototype.explain

[kumavis]

if npm/arborist#241 is acceptable, I will update this PR to include a bundled decoration for edges as well. very helpful for seeing where in the branch of a dep tree the bundle happened

[kumavis]

here's the improvement with bundled flag on Edges

[nlf]

this is great!