Proposal to remove implicit state changes #40
Description
Currently, CodeChain has two implicit state changes.
One is storing pending rewards or giving rewards at the end of a block; the other is giving rewards at the beginning of a term.
It's because the behavior differs depending on the consensus algorithm.
However, it makes implementing an indexer hard because it also needs to implement the rule of distribution to track the amounts of CCC.
So I suggest adding two transactions for storing pending rewards and giving rewards.
Even the validators still need to calculate the rewards rule to validate a block since the transactions will help when implementing the indexer and light client without calculating the complicated rewards rule.