[BIP-220] Enable bb-ma2-USD Gauge [Ethereum]

Transaction Payload: https://github.com/BalancerMaxis/multisig-ops/pull/118 Summary:

The bb-ma2-USD pool is a Composable Stable Pool that facilitates trades between three US Dollar stablecoins (USDC, USDT and DAI). These are each wrapped through Morpho-Aave v2’s market, providing LPs with additional yield.

We propose adding a gauge to this pool.

References/Useful links:

• Morpho Website
• Documentation
• Github Page
• Communities: Discord, Forum
• DApp
• Analytics

Protocol Description:

Morpho-Aave is a peer-to-peer layer built on top of Aave. It is a lending pool optimizer: it improves the capital efficiency of positions on lending pools by seamlessly matching lenders and borrowers peer-to-peer. By doing so, Morpho-AaveV2 enhances the rates of AaveV2 while preserving the same experience, liquidity, and parameters (collateral factors, oracles, etc.) as the underlying pool.****

USDC is the dollar-backed stablecoin issued by Circle. USDT is the dollar-backed stablecoin issued by Tether. DAI is the decentralized overcollateralized stablecoin by MakerDAO.

Motivation:

The Morpho-Aave boosted pool enhances Balancer's capacity to improve capital efficiency through linear and boosted pool architecture. While Aave has been commonplace for Balancer boosted pools in the past, the bb-ma2-USD pool enables LPs to access improved yield compared to the original bb-a-USD pool. Encouraging liquidity on the pool through gauges will leverage this improved yield, making it even more appealing for LPs. This will ultimately result in better trading conditions for the three stablecoins.

Specifications:

1. Governance: Morpho-Aave Core contracts are owned by a 5/9 multisig safe with a 24-hour timelock. Multisig decisions reflect the choices of the Morpho token holders. A 3/9 multisig can execute quick, non-critical actions, such as pausing a market when required. For more information on Governance, see this page.

   USDC and USDT are centralized and do not have governance forums. DAI is collateralized by MakerDAO.

2. Oracles: Morpho-AaveV2 relies on the same oracles as AaveV2, used in bb-a-usd.

3. Security:

   • Audits: The protocol has been audited numerous times by the best audit firms in the world
   • Bug Bounty: Moprho has a Bug bounty of $555,555, live since 17 June 2022
   • Formal Proving: Morpho formally proves its contracts using Certora and Morpho Labs’s internal formal prover.

4. Centralization vectors: USDT and USDC are inherently centralized.

5. Market History: See USDC here, USDT here, and DAI here.

6. Value: LPs will earn the yield on the idle liquidity deposited on Morpho-Aave. LPs & Balancer will earn the swap fees. Note that the Morpho-Aave protocol does not take any fees.

Pool address: 0xCAa052584b462198A5a9356c28bcE0634D65f65C Uncapped Gauge Address: 0x254f3a52Ba9e0cac4E32B648d129529622D1A46c