Ability to add form confirm/cancel button labels

We repeat a lot of templating code in our forms. It makes sense to abstract
some of these repetitive logic and reduce the clutter. This is an unintrusive
patch aim to give users ability to specify confirm and cancel labels in the
form class.

Change-Id: I6eba93c61a3a6a94ac7b42f199bfb95df86e96b6
Partially-Implements: blueprint form-template-to-view
Made Admin State choice more human readable

The Admin State choices in create forms throughout horizon
were not very clear, this patch presents that choice in a much more
readable and understandable way. The field is changed from a boolean
field to a choice field with the different states, making it more
obvious what is being decided.

Change-Id: I7091e5ccf91c57d3f64e2d4415bed952d09ada71
Closes-Bug: 1370322
Merge "Ability to add form confirm/cancel button labels"
Merge "Made Admin State choice more human readable"
Merge branch 'master' of https://github.com/openstack/horizon