RESTful API to return the latest shutdown events

[RitaMAllenCA]

@hectoratcasper commented on Tue Mar 14 2023

https://docs.google.com/document/d/1vBRbBmij9HHotY_8HIaUKk5a9Kq9Rqgxlk-UAE_F7xs/edit?pli=1

The Shutdown event is emitted when the node is about to shut down, usually for an upgrade. This causes a termination of the event stream since the server is shutting down. The SSE sidecar stores this event in the shutdown table:

We require a new RESTful API for this event that would allow operators to get the latest node shutdown events filter by a limit:

<HOST:PORT>/shutdown?limit=10