Get username & expiry along with token

[bsoule]

Lichess gives only the issued token in the "obtain access token" phase of the oauth dance, and we could potentially override the omniauth defaults to make another call to lichess /api/token/test endpoint to annotate the returned token info with an expiry date and a username.

Or we could leave it up to the client to do that and get additional information on the Beebody side of things as we need it.