Remove AuthMethod and add access token to RestApi

Authentication for API calls will be handled using an access token
in the "Authorization: OAuth access_token" style. Browsers do not
use this when making requests unless they use an XmlHttpRequest.
If the value used as the access_token is not available cross-site
then the API call cannot be made by hijacking attempts.

Change-Id: I33654bcaa247cb95a57b03d2df112ca95e970185
22 files changed