Includes AuthOpts struct and AuthRef interface, plus an Identity v2
password auth implementation.
Note: the examples work, the objectstore_test is broken, will be fixed
along with additional session and auth tests.
This is the initial implementation of a Session object that handles
the REST calls similar to the new Session in python-keystoneclient.
It will be expanded to utilize a callback to an appropriate authentication
handler to re-authenticate as required.
This is intended to replace CallAPI in the util/util package.