Modify client package

[jimni1222]

Subtask of #3

• Implement block reward logic
• Implement fee operation logic
• Implement balance query logic
• Modify the other logic for Klaytn
• Modify client unit test
• Check the handling method if the reward percentage distribution is not divisible by an integer (block_response_363753, block_response_363366) -> remain rewards need to be added to KGF address (In https://github.com/klaytn/klaytn/blob/d5033e6376f39a691296044bf0f47e8977b1e105/reward/reward_distributor.go distributeBlockReward function) -> #36