kaiax/staking,reward: Introduce consensus liquidity

[hyeonLewis]

Proposed changes

This PR introduces consensus liquidity to staking, reward modules.

The consensus liquidity will be activated for network activating Prague hardfork and istanbul.policy == 2 && reward.deferredtxfee = true.

Staking module

When GetStakingInfo, if condition met, it reads CLInfos from CLRegistry defined in KIP-226. If Registry hasn't been installed (by any reason), it skips CL and don't panic. If CLRegistry hasn't been registered, it will return empty arrays.

Reward module

When ConsolidatedNodes(), if condition met, it consolidates CLInfos by CLNodeId, not CLRewardAddr.

Let's assume we have following entries in AddressBook and CLRegistry.

// From AddressBook
NodeIds = [n1, n2, n3]
CNStaking = [c1, c2, c4]
RewardAddrs = [r1, r1, r2]

// From CLRegistry
CLNodeIds = [n2]
CLPools = [p1]
CLRewardAddrs = [clr1]

Then, the clr1 isn't neither r1 nor r2. But it will be consolidated into [n1, n2] since it has CLNodeId == n2. The result consolidated nodes are:

{
  NodeId = [n1, n2]
  StakingContracts = [c1, c2]
  RewardAddr = [r1]
  StakingAmount = balance(c1+c2)
  CLStakingInfo {
    CLNodeId = n2
    CLPoolAddr = p1
    CLRewardAddr = clr1
    CLStakingAmount = balance(p1)
  }
}, 
{
  // Node3
  ...
}

If CLNodeId doesn't belong to any of node, then it'll be ignored. Note that CLNodeId can be any of NodeId, not first NodeId.

Reward distribution

If validator has CL, then the staking in CL also summed up to total staking amount if staking in AB >= minStaking.
The excess staking amount will be calculated by:

// Before Prague
excess = StakingAmont > minStaking ? StakingAmount - minStaking : 0

// After Prague
excess = StakingAmont >= minStaking ? StakingAmount + CLStakingAmount - minStaking : 0

Both the proposer and staking rewards will be proportionally distributed to RewardAddr and CLRewardAddr. For proposer, please see #specWithProposerAndFunds.

API

The kaia.GetStakingInfo will be affected and CLStakingInfos field will be null before prague HF or empty CLRegistry entries.

Testing

The unit tests are included in this PR. I'll start testing in private network once this PR stabilized.

Types of changes

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• Bugfix
• New feature or enhancement
• Others

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• Lint and unit tests pass locally with my changes ($ make test)
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Further comments

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