Hybrid Inflation Model

[PierreOssun]

Pull Request Summary

closes #1049

This PR adds a new pallet block_rewards_hybrid that is forked from pallet-block-reward.
Changes:

• It first calculates the rewards then increase total issuance and then distribute the reward. It's closer to solution 2. expressed in [Tokenomics][Meta] Tokenomics v2 #1023 . I chose this over the first solution because it avoids to issue as well as burn total issuance in on_timestamp_set hook and it looks not idiomatic.
• the reward of the treasury is now fix
• stakers receive the dynamic part in exactly same way (untouched).
• Added tests to ensure it works under different TVL scenario & that total issuance is only increased by rewarded amount

Before
A fixed amount of BLOCK_REWARD was distributed (to stakers, dapps, collators, and treasury) so inflation was fixed. The TVL (fluctuating) was distributing the reward_config.adjustable_percent rewards between stakers and treasury.

Now
The TVL (fluctuating) is not distributing the reward_config.adjustable_percent rewards between stakers and treasury anymore. instead the proportion is only distributed to the stakers (and is calculated the same way). The remaining proportion that was previously reward to treasury is now just omitted (not minted), that's why the rewards per block/inflation is now dynamic.

To help review
The main update and code logic updated from previous pallet is in on_timestamp_set and the two new functions calculate_rewards and distribute_rewards (HERE in master).

Check list

• added or updated unit tests
• updated Astar official documentation
• added OnRuntimeUpgrade
• updated spec version
• updated semver

[Dinonard]

Nice, great work!

[Dinonard]

LGTM

[PierreOssun]

/bench shibuya-dev pallet_block_rewards_hybrid

[github-actions]

Benchmarks job is scheduled at https://github.com/AstarNetwork/Astar/actions/runs/6889749488.
Please wait for a while.
Branch: feat/hybrid-inflation
SHA: 6b22734

[github-actions]

Benchmarks have been finished.
You can download artifacts if exists https://github.com/AstarNetwork/Astar/actions/runs/6889749488.

[shaunxw]

Looks good in general!

[PierreOssun]

/bench shibuya-dev block_rewards_hybrid

[github-actions]

Benchmarks job is scheduled at https://github.com/AstarNetwork/Astar/actions/runs/6892810709.
Please wait for a while.
Branch: feat/hybrid-inflation
SHA: 0077580

[github-actions]

Benchmarks have been finished.
You can download artifacts if exists https://github.com/AstarNetwork/Astar/actions/runs/6892810709.

[github-actions]

Package	Line Rate	Branch Rate	Health
precompiles/utils/macro/src	0%	0%	❌
pallets/unified-accounts/src	83%	0%	✔
chain-extensions/pallet-assets/src	0%	0%	❌
precompiles/dapps-staking/src	93%	0%	✔
pallets/block-reward/src	85%	0%	✔
primitives/src/xcm	66%	0%	➖
chain-extensions/types/unified-accounts/src	0%	0%	❌
pallets/dapps-staking/src	81%	0%	✔
chain-extensions/unified-accounts/src	0%	0%	❌
pallets/dapps-staking/src/pallet	85%	0%	✔
primitives/src	65%	0%	➖
pallets/contracts-migration/src	0%	0%	❌
precompiles/utils/src	55%	0%	➖
pallets/xc-asset-config/src	53%	0%	➖
chain-extensions/types/xvm/src	0%	0%	❌
pallets/collator-selection/src	69%	0%	➖
chain-extensions/dapps-staking/src	0%	0%	❌
pallets/xvm/src	40%	0%	❌
pallets/block-rewards-hybrid/src	87%	0%	✔
pallets/dynamic-evm-base-fee/src	81%	0%	✔
pallets/ethereum-checked/src	48%	0%	❌
chain-extensions/xvm/src	0%	0%	❌
precompiles/xvm/src	75%	0%	➖
precompiles/xcm/src	75%	0%	➖
precompiles/utils/src/testing	38%	0%	❌
precompiles/assets-erc20/src	77%	0%	➖
chain-extensions/types/dapps-staking/src	0%	0%	❌
chain-extensions/types/assets/src	0%	0%	❌
precompiles/sr25519/src	79%	0%	➖
precompiles/substrate-ecdsa/src	78%	0%	➖
Summary	57% (2275 / 4014)	0% (0 / 0)	➖

Minimum allowed line rate is 50%