Implement initialisation

[ryankurte]

Initialisation needs to interact with plugins for address discovery and registration, this process must also be re-executed periodically to manage network changes

Rough process:

• Discover local address(es) (and infer interface address if allowed)
• Attempt UPnP routing to external services (and use this if allowed)
• Attempt mDNS registration
• Publish (new) contact information (if specified)