This change adds support for the client credentials grant type to the
token api. The client credentials grant allows for a client to
authenticate with the authorization server and obtain a token to access
as itself. Per RFC 6749, a refresh token should not be included with
the access token and as such a refresh token is not issued when the
client credentials grant is used.
The addition of the client credentials grant will allow users
authenticated with mechanisms such as kerberos or PKI to obtain a token
that can be used for subsequent access.
Ioannis Kakavas
Jay Modi
Lisa Cawley