api: Add support for more types of (VM) console

Modify the current 'console' action to support VNC WebSockets (requires
snf-vncauthproxy=1.6). Also add support for the three OpenStack Compute
console actions (VNC, RDP, Spice), supported by Nova. RDP (Hyper-V
specific) and Spice currently return a '500 Not Implemented' cloud
fault.
ui: Switch to the noVNC websocket client

Update the console API call to request a vnc-wss console and replace the
TightVNC Java client with the noVNC HTML5 / websocket-based client.
Update Changelog
Merge branch 'feature-vncws' of https://github.com/psomas/synnefo into develop