Add support for Voting Incentive Markets (HH, Paladin) #528

Problem statement

We are more and more relying on voting incentive market data like HiddenHand and Paladin. Currently, these data providers don't store historical data consistently (HH price data only takes current prices, not historicla ones, Paladin doesn't have historical data at all).
Therefore, we should store it in our backend by doing end-of-round snapshots and exposing that data via the API

Specifications

1. Expose data through api-v3 query object with input of market (hh, paladin), space (aura balancer) snapshot timestamp for single round data.
2. If possible provide aggregated data for all timestamps with a single query if no timestamp was provided, response sorted as array with parent object ref as timestamp, e.g.:

{'aura': ['1656378000': { ... }, '1657591200': { ... }, ] }

HiddenHand

• Endpoint for AURA
• Endpoint for Balancer
• Endpoint for Beethoven X

To obtain data for a specific round, one needs to provide the timestamp after the endpoint:

• Aura: First round ended at timestamp 1656378000 and increases monotonically by 1213200 s (2 weeks).
• Balancer: First round ended at timestamp 1649894400 and increased monotonically by 604800 s (1week)

Paladin

Swagger Docs