Group CRUD and Management in Admin Dashboard.

Add support for CRUD on Group for admin users. It also includes
the user management capability for the group.

Keystone revokes the token when a user is added or removed from the
group. If the logon user is added/removed from the group, the user
will be redirected to the login page.

This feature is only exposed if the user explicitly set horizon
for keystone V3.

Implements blueprint admin-group-crud

Change-Id: I1b5456af80bcc35e9d16ac6ba6792e82704e76fd
Improve test stability

Under some circumstances, Canada/Newfoundland (UTC -03:30)
can not be found as answer in tests. This patch improves
stability here by using cities with the same distances to
UTC and UTC DST.

Fixes bug 1184901

Change-Id: I7d5739a7c7a504c22cceebeaa3331637993e34ae
Merge "Group CRUD and Management in Admin Dashboard."
Merge "Improve test stability"