Provide Juju details on Horizon

[Mark Shuttleworth]

Please can we restore the ability to view a Juju stanza for a user of Ubuntu OpenStack?

It should take the form:

  <environment-name>:
        type: openstack
        auth-url: http://192.168.9.97:5000/v2.0
        region: <region>
        auth-mode: userpass
        use-floating-ip: true
        network: <default-network-for-project>
        tenant-name: "<project-name>"
        username: "<username>"
        password: "Your Password Here"
        authorized-keys: <your ssh public key>

i.e. pre-fill network, tenant, and username, and invite the user to provide password.

This should be provided on the Horizon "Overview" page (and is specific to the combination of tenant and user) until we have the Juju GUI integrated to Horizon.