Extend PoolCurrentPaydayInfo and PoolInfoResponse.

[td202]

Purpose

Depends on: Concordium/concordium-base#587

Parse the extended PoolCurrentPaydayInfo and PoolInfoResponse from GRPC.
Note that only the raw GetPoolInfo command displays these records, and that uses the JSON serialization defined in base.

Changes

• Update the FromProto instances for PoolCurrentPaydayInfo and PoolInfoResponse.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.