Add UserID to search results

[ChrisPenner]

Overview

In some cases, like granting a user permission to a new repo, it's safest to use a user's UserId rather than their handle, since the user Id is immutable.

To enable this, we provide the UserID in search results alongside the handle, name, and avatar.

Implementation notes

• Adds the userId field to the User search result JSON
• Updates transcripts, and ports the code-browse transcripts to the new format.

Test coverage

See transcripts

[ChrisPenner]

Here's an example response, except the transcript runner filters out UUIDs since they're random, but you get the idea :)