This patch adds the test_federation file with some tests
for Identity Providers, the tests are not supposed to be
exhaustive, they are rather simple and intend to cover
the basic actions in the Identity Provider handling.

More complete tests should be added later.

Change-Id: Ibe618dcd646912060b1785d8d72fd526dd4a083b

keystoneclient/tests/functional/v3/test_implied_roles.py is a test
module, and it doesn't have main entry, hence the executable flag
is not needed.

Change-Id: Ic226607afcd82d2411cbe1cd5439b0db5f77728c

While the entity for an inference rule should be thought of as a
resource, the rules are essentially relationships between roles.
The `implied_role` API is linked with the role API, and thus the
client functions are part of v3/role.py.  However, it does not
map completely cleanly to the Crud baseclass, and requires
some custom URL generation.

Change-Id: I80a40e88b571fe9b0eca3af8b705ea79f28eb904

In the cross project workshop "Establishing key themes for the Mitaka
cycle" [1] during the Mitaka summit, one of the agreed point was to
implement functional tests for the client libraries. [2]

Later on, this will serve to improve our backward compatibility for
client libraries. See I72e4e9cfa0539f6b326a0296c065fa3cb754f8ae

In preparation to implement the functional tests for both v2 and v3
clients, this patch initializes the new directories and adds the base
test classes: V3ClientTestCase and V2ClientTestCase.

Each class instantiates its specific keystoneclient version via
os-client-config either based on a clouds.yaml config file or from the
environment variables.

[1] https://mitakadesignsummit.sched.org/event/edd78ade4c7c92581a7cabc26019a85a
[2] https://etherpad.openstack.org/p/mitaka-crossproject-themes

Change-Id: Ia73d72d5f87051fb46d733782275b548874a1def