Implementing getTotalBurnt, getTotalCirculatingSupply API

[aidan-kwon]

Background
Blockchain data services such as CoinMarketCap need to know the total burnt amount of KLAY and the total circulating supply.
They can calculate the number with on-chain data, however, it requires lots of time and engineering resources.
If we implement APIs for that information, they can quickly get it in anytime.

Consideration

1. klay_getTotalBurnt

• Two kinds of KLAY burning methods are used generally
  • KIP71 Burn mechanism: half of tx fee will be removed from the state
  • Sending to 0xdead: Anyone can send KLAY to 0xdead address to burn KLAY
• We can consider two types of returns depending on an input parameter
  • klay_getTotalBurnt([Additional burn address]): if Additional burn address is nil, return only the burnt amount by KIP71 Burn mechanism. With an input, we can add the balance of the input address
• We may need to store the data in the database. In that cases, find a safe way to calculate all previous block data

2. klay_totalCirculatingSupply

• We need to collect requirements and definition from data services or business team to define the specification

[smseo]

@aidan-kwon IMO, we should provide klay_getTotalSupply, not klay_totalCirculatingSupply because klay_totalCirculatingSupply might have to rely on offchain data.

Let's first focus on klay_getTotalBurnt and klay_getTotalSupply.
cc @kjeom

[exalate-issue-sync]

Exalate commented: Issue Created by: aidan-kwon

[blukat29]

Implemented by #2148.