Adding API to get the User Role list per project.
Get the role list from tokenObjs which is stored in req.session object.
If a user adds some role, that will not be available with this API, the user
must have to logout and then login back to get the role lists. As the tokenObjs
is updated at login time, and we do not store user auth details.
If the role-list is being fetched for a new project which was not available
while login, then UI gets redirected to login page.

Change-Id: Ieb8ae35116862587e2834ede25ecfe5be5f46c21