Search should also surface team matches

[carols10cents]

We have team pages now (ex: https://crates.io/teams/github:pistondevelopers:pistoncollaborator), but there's currently no way to navigate there unless you find a crate owned by that team and click on their icon.

It'd be neat if, when you searched for "piston", there were search results for teams as well as crates, so that you could more easily discover team pages that would show groups of crates you might be interested in.

Team search results should look visually distinct from crate search results.