Currently we identify CB users by a uuid. This is because there are a small set of reviews that were imported from a 3rd party site and weren't linked with a musicbrainz account. 400 of 1400 users have no musicbrainz id.

However, we require a musicbrainz account to be able to write reviews, and for better integration we should allow for usernames to be used when referring to users.

• Update views and query parameters on the website and in the API to support a user uuid or a musicbrainz id
• Ensure that we can update a username if it changes in musicbrainz
• If a username changes, decide if we want to keep a redirect from the old url to the new url