Implement unauthenticated API endpoints and aggregate Agent queries for BoTC

[pospi]

Bank of the Commons wants these features for integration with other sites:

• Add an edge for memberCount to the organization type, which just does an aggregate of the members query & returns the count.
• Add another special EconomicResourceCategory for "shares" like we have for currency & inventory at the moment, plus another aggregate query type which just returns the count of the found records.
• Add a non-authenticated query to get an EconomicAgent by ID. Check visibility = "public". These kinds of agent queries would have access to less data than the authenticated ones (only the aggregates, so far)