Problem: redundant code for payout key

[rstormsf]

https://github.com/oraclesorg/oracles-contract/blob/master/src/KeysStorage.sol#L108

Reason: There is no enforcement or validation how miner's will store his/her funds. The contract should only handle miner's & voting's keys to validate the input.

The oracles's script can and should be able to use any payout public keys.

Solution: Remove any code that handles payout logic for optimization