Hyper-V RDP console access

This is the client side counterpart of the following Nova blueprint: https://blueprints.launchpad.net/nova/+spec/hyper-v-rdp-console

Hyper-V, unlike the majority of the hypervisors employed on Nova compute nodes, uses RDP instead of VNC as a desktop sharing protocol to provide instance console access, which means that novnc / xvpvnc are not a viable options for providing console connections to Hyper-V hosted instances.

Goals:

1) Add Hyper-V RDP console access support to Openstack
2) From a user perspective, console access should be handled in a way as consistent as possible between hypervisors.