[compute] Additional server admin actions

Issue: https://github.com/aviator/aviator/issues/16

Included:
3.1.1. Pause Server
3.1.2. Unpause Server
3.1.3. Suspend Server
3.1.4. Resume Server
3.1.5. Migrate Server
3.1.8. Lock Server
3.1.9. Unlock Server
3.1.12. Reset Server State

Not included:
3.1.6. Reset Networking on Server
3.1.7. Inject Network Information
3.1.10. Back up Server Instance
3.1.11. Live-Migrate Server
3.1.13. Evacuate Server