Errors during a pending activation

[simonrankine]

At present IS-05 relies on the client to notice where a pending activation has failed to happen by checking back with the API. In the event a client does check back, the API does not provide any information on the nature of such a failed activation. Possible resolutions include:

• Providing some information about the success or failure of the previous activation in the active endpoint.
• Providing history of previous activations at a new new endpoint, including error information.
• Adding a websocket to IS-05 which would provide information about scheduled activations to subscribers when the are completed.

This would potentially simplify client implementations, and provide better feedback to users as to why errors occurred during activations.