Extend the OpenRemote client with the service registration mechanism

[dominiquekleeven]

Summary

Extend the OpenRemote client implementation so that it allows a service to actively register with the Manager and communicate its state and properties, such as URL and name.

It might also make sense to extract the client into a separate package (#35).

Goals

See openremote/openremote#1686 for API details on the OpenRemote side of things.

• Add service.register(...) method:
  • Registers the service with the OpenRemote Manager
  • Sends service metadata such as name, URL
• Add service.heartbeat() method to send a manual heartbeat
• Add service.deregister(...) method
• Scheduled task for registering a service and keeping it alive via heartbeats on an interval

Dependencies

• Depends on: Added Keycloak integration #34
• Related to: Package up re-usable components -- keycloak middleware, openremote client implementation #35

[dominiquekleeven]

See PR openremote/openremote#1979

[dominiquekleeven]

BLOCKED BY: openremote/openremote#1979