GraphQL network supply API

[steven-sheehy]

Problem

As a consumer of the mirror node GraphQL API, I'd like to be able to get information about network supply.

Solution

Implements the network { supply(timestamp: Timestamp): NetworkSupply! } query. Reference the /api/v1/network/supply REST API for relevant queries.

Tasks

Beta Give feedback

1. Copy relevant schema over from HIP
2. Add a NetworkController and test
3. Update EntityService
4. Update EntityRepository to retrieve current supply and timestamp
5. Add a AccountBalanceRepository and test to get historical supply
6. Support query by optional timestamp
7. Create a NetworkSupplyMapper and test that maps all scalar fields
8. Add smoke test to postman.json

Alternatives

No response