Adjudicator watcher for the bot

[tomclose]

In order to operate the hub safely, we need to be able to monitor the state of the chain.

I suggest we structure this similarly to the app: we have a background worker/service whose job it is to mirror the state of the adjudicator into the database (for channels that we care about) - and potentially trigger an alert when something changes.

The goal of this strand of work is to write a worker that does this.

It's likely that people have already solved this problem. For example, Spankchain use chainsaw. Part of this work should be to do a quick search/evaluation for other solutions to see if there's anything robust that fits our needs. That said, I don't think our needs are that extensive, so it might be that the right path here is just to build it.

[kerzhner]

This is an overview card. All in-progress work is tracked in Related Cards.