Allow for Node to Provide PoST Data Information via GRPC

[hakehardware]

A few months ago I created a Python script that acted as a Textual User Interface (TUI) for go-spacemesh. This used GRPC to gather data about go-spacemesh and present it in the CLI. This was very helpful for many as it was able to aggregate data across many go-spacemesh instances.

With v1.3 I am not able to query post setup status to get information about the PoST Data. This makes it difficult to give aggregated totals of PoST data size like I did previously (by summing the total numunits reported by post setup status). There are other ways I could do this but none of them are as simple as just calling the grpc endpoint. I'd like for this data to be available via go-spacemesh as the post-service nodes are not always online.

These TUIs are extremely helpful for those that want a TUI wrapper around go-spacemesh to view information about their nodes.

[lrettig]

@hakehardware thanks for raising this. Have you had a chance to look at the post-rs service and its API? Maybe the data you need is there. See https://github.com/spacemeshos/post-rs/blob/main/service/README.md