Add paydayCommissionRates logic

[DOBEN]

Addresses #367

Purpose

query ($bakerId: Long!) {
  bakerByBakerId(bakerId: $bakerId) {
    state {
      __typename
      ... on ActiveBakerState {
        pool {
          paydayCommissionRates {
            transactionCommission
            bakingCommission
            __typename
          }
          commissionRates {
            transactionCommission
            bakingCommission
            __typename
          }
        }
      }
    }
  }
}

Related https://linear.app/concordium/issue/CCD-142/implement-bakerpool

Changes

Add paydayCommissionRates logic.