Refactor code around Console support

[Julie Pichon]

Initially Horizon only supported VNC. As support for new console types was added, the code was expanded for each console without necessarily looking at the whole, and now the code could use a bit of freshening up. This is particularly obvious in tabs.py.

https://github.com/openstack/horizon/blob/master/openstack_dashboard/dashboards/project/instances/tabs.py#L55

From a comment on https://review.openstack.org/#/c/44257/ :

"We should have a common Console class that's aware of the different types, and a common means of detecting which console type to use for the instance rather than the chain of try/except statements."

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/78348

[Leandro Ignacio Costantino (leandro-i-costantino)]

bp created at https://blueprints.launchpad.net/horizon/+spec/refactor-console-support based on review comments.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/78348
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=ded54e6f5d4885e4422867ab52860488c0fe8a22
Submitter: Jenkins
Branch: master

commit ded54e6f5d4885e4422867ab52860488c0fe8a22
Author: Leandro I. Costantino <email address hidden>
Date: Wed Mar 5 10:56:25 2014 -0300

    Refactor code around Console support

    Add a console module to handle the different kinds on remote consoles
    supported (vnc, rdp, spice ) and refactor the code
    to use console.get_console.

    In the future, a matrix based on HyperVisor could be added
    in case that only one type of console is supported.
    Ex: HyperV <=> RDP

    Change-Id: If448b7c9d953765b9b56ee14b39975d951ffd92c
    Implements: blueprint refactor-console-support
    Closes-Bug: #1287881