Developers should have community-level data on online status

[holmesworcester]

We should be able to see when nodes think they are online, and when they are actually converged with other online users.

Proposed solution:

1. Every client sends heartbeat orbitdb entry to community when it comes online, and every n seconds after that.
2. Heartbeat messages include head, and possibly other data e.g. which peers are connected.
3. This data does not need to display in the UI but we can export it somehow and see it.

We also might want some intermediate data on their process for converging, e.g. attempted connections, heads exchanged, replication, etc., but this might not be necessary.