Feature Virtio
Enhance CIRCLE to use virtio-serial ports to communicate with the agent.
⚠ WARNING ⚠
Requires (virtio branch):
🆕 agentdriver
🆕 vmdriver
Tests:
* new-windows agent ✅ (Working virtio with update watchdog for service restart)
* new-linux agent ✅
* legacy-windows agent ⚠ (Old windows agent can't update)
* legacy-linux: ✅ Working update with less than 16k tar
See merge request !205
