Add first place rank information to /get_user

[tybug]

It would be nice to see what first place ranks a user has. For circleguard, first place ranks would be prioritized and screened first, since especially in the case of +FL plays they tend to be cheated (remodded). First pace ranks are also not necessarily worth enough pp to even get into a user's top plays, making it inaccessible from the normal /get_user_best endpoint.

[peppy]

it would be a different endpoint if anything. also api v1 is relatively feature locked for the time being. osu-web would be the correct place to add me functionality