[BIP-218] Enable bb-s-USD Gauge [Ethereum]

PR with payload

Summary:

This pool uses the ComposableStablePoolFactory-v3 and is composed of three Sturdy Finance linear pools. The underlying tokens are USDC, DAI, and USDT. These will each be wrapped through Sturdy's stable coin lending market to earn LPs additional yield. This gauge would enter as a “core pool” under BIP-19, meaning protocol fees earned by this pool would be used to bribe for votes on it. The gauge can be uncapped based on the contents being all large cap stable tokens. Sturdy offers a WETH lending markets as well, but the natural first step is to work with stable tokens. This diversifies the options for stablecoin LPs on our platform to optimize their positions.

References/Useful links:

Sturdy: Link to: • Website • Documentation • Github Page • Communities - Discord USDC: Link to: • Website • Documentation • Github Page • Communities - Coingecko link

Protocol Description:

Sturdy finance utilizes a leveraged borrowing market in order to earn the lenders returns for their user’s to deposit digital assets and receive yield. Borrowers then can use the funds on whitelisted farms on several protocols, Balancer being one of them. The farming rewards are then split between lenders and borrowers. More information on Sturdy's structure strategies can be seen here. USDC is the dollar backed stablecoin issued by Circle. DAI is the decentralized overcollateralized stablecoin by MakerDAO. USDT is the dollar backed stablecoin issued by Tether.

Motivation:

Balancer’s ability to increase capital efficiency using linear and boosted pools is taking shape across the protocol. This Sturdy boosted pool fits Balancer’s initiative to be a protocol where LPs can safely tap into external yield sources, while maintaining effective liquidity for swapping. This will earn both LPs and the DAO yield and provide Idle with a place for their wrapped tokens to easily be swapped and deposited as the pool increases in TVL.

Specifications:

1. Governance: USDC are centralized and does not have a governance forum. DAI is collateralized by MakerDAO. Sturdy's governance details can be seen here. Their token has not yet been released.
2. Oracles: This pool only relies on the rate providers of the linear pools to inform when yield is earned.
3. Audits: See Sturdy's here
4. Centralization vectors: Sturdy's multisig signers are noted here.
5. Market History: See USDC here.
6. Value: LPs & Balancer will earn the protocol fee on underlying bb-s-USD as well as swap fees. BIP-19 will incentivize TVL to continue to grow here with trading volume and this implementation will continue to draw in new volume, as well as showcase the power of these pool types.

Link to pool: 0x779d01F939D78a918A3de18cC236ee89221dfd4E Link to gauge: 0xFd29298041eA355cF7e15652689F2865443C3144

Specification

The DAO Multisig 0x10A19e7eE7d7F8a52822f6817de8ea18204F2e4f will interact with the AuthorizerAdaptor at 0x8F42aDBbA1B16EaAE3BB5754915E0D06059aDd75 and call performAction with the GaugeController at 0xC128468b7Ce63eA702C1f104D55A2566b13D3ABD for the target(address) argument and using 0x3a04f900 followed by the gauge address 0xFd29298041eA355cF7e15652689F2865443C3144 and the corresponding gauge type for the data(bytes) argument.

data(bytes) : 0x3a04f900000000000000000000000000fd29298041ea355cf7e15652689f2865443c31440000000000000000000000000000000000000000000000000000000000000002