[BIP-201] Enable bb-ag-USD Gauge [Gnosis]

PR with multisig payload

Summary:

This pool uses the ComposableStablePoolFactory-v3 and is composed of three Agave Finance linear pools. The underlying tokens are USDC, USDT, and DAI. These will each be wrapped through Agave's 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. Agave is a fork of Aave and native to the Gnosis chain making it the logical choice for boosted rewards for Balancer LPs to access on the new network.

bb-ag-USDT represents boosted USDT, and bb-ag-DAI represents boosted DAI.

References/Useful links:

Link to: • Website • Documentation • Github Page • Communities

Protocol Description:

Agave, as stated, is a direct fork of Aave's money market, this encompasses both a lending and borrowing side for users. Agave was built by 1Hive to bring Defi to what is now Gnosis Chain for lower fees to participate overall. 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:

This Agave boosted USD pool will form the cornerstone of our USD stable liquidity on Gnosis Chain. The boosted APR yield to this pool that will persist for users organically and kickstart a flywheel for incentives to drive liquidity depth on Gnosis Chain. By expanding to a new chain, getting boosted pools off the ground first thing sets a precedent for net positive growth for Balancer and LPs on the network.

Specifications:

1. Governance: Find more information about MakerDAO governance here. USDC and USDT are centralized and don’t have governance. Agave's forum can be seen here.
2. Oracles: This pool only relies on the rate providers of the linear pools to inform when yield is earned.
3. Audits: See here.
4. Centralization vectors: There are centralization risks with USDC, DAI, and USDT, though the market has clearly accepted those as minor for now.
5. Market History: See here.
6. Value: We will earn the protocol fee on bb-ag-USD yield, plus trading 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: 0xFEdb19Ec000d38d92Af4B21436870F115db22725 Link to gauge: 0x25D6F29429bccCc129d1A3e2a5642C8B929BCC07

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 0x25D6F29429bccCc129d1A3e2a5642C8B929BCC07 and the corresponding gauge type for the data(bytes) argument.

data(bytes) : 0x3a04f90000000000000000000000000025d6f29429bcccc129d1a3e2a5642c8b929bcc070000000000000000000000000000000000000000000000000000000000000002