Aggregate data storage report of all users

[djing-chan]

We could let users publish their data storage reports to the network and use that data as a benchmark to compare ones own state of network data to see if there is some data missing. It would also give some insight about the quality of data distribution and health of the network.

The publishing need to be done to not link to the node to not add any risks from node load data which could be abused for attacks. We also need to ensure that we get only one data item per node and that the data have short TTL. To have a UID per node which does not reveal the nodes network address we can use a private per node salt hashed with the pubkeyhash. If we use AuthenticatedData we also need to ensure to use a different keypair to not link to the nodes identity (even if its just the default identity as the default node could become subject of an attack).

For comparison with aggregated data we need to account for the time stamp as only comparison with recent data makes sense to detect missing data. If missing data is detected we can trigger a inventory request.