Hyper-V driver RDP console access support

Implements: blueprint hyper-v-rdp-console

Hyper-V uses RDP to provide graphical console access, unlike most other
hypervisors which use VNC for this purpose.

This patch implements get_rdp_console in the Hyper-V driver.

Change-Id: I92e6c4921ff42c1bac2c76dfa1570160a0d11338
Merge "Hyper-V driver RDP console access support"