feat: enhance device registration and health management on ThingsBoard flows

[rina23q]

This PR updates many things. Highlights:

Enhance registration

• thingsboard-registration flow: responsible for registering a new child device and service.
  • If a message for unregistered entity is coming, the flow puts it into the pending messages store.
  • When registration, adds entityId/deviceName, deviceName/entityId pairs to KV stores.
  • Other flows (thingsboard, thingsboard-rpc) can query the entityId-deviceName 1:1 mapping from context.mapper KV store.
  • The TB device name can be configurable by name in the entity registration payload. Also, the device profile can be configurable by type in the entity registration payload.

  {
     "@parent": "device/main//", <- reserved by thin-edge
     "@type": "child-device", <- reserved by thin-edge
     "name": "child device 0", <- will be used as ThingsBoard device name
     "type": "child-profile" <- will be used as ThingsBoard device profile
  }

Health management

• thingsboard flow: responsible for the health status management
  • Converts status/health message to TB telemetry
  • Periodically publishes a heartbeat message to the main device, and keeping updates the statuses of the entities.

---

I'm still not sure if having 3 flows for ThingsBoard is better than having 3 steps in one flow. What is the best practice?