[BIP-72] Enable wstETH/USDC Gauge [Arbitrum]

Summary:

This pool uses the new weighted pool factory which allows us to apply the protocol fee to yield bearing tokens. 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. Since all fees collected on Arbitrum are distributed through bribes, this pool will also receive bribes from those fees in proportion to this pool's TVL relative to other Arbitrum core pool TVL.

References/Useful links:

Link to: • Website • Documentation • Github Page
• Communities • Other useful links?

Protocol Description:

wstETH is liquid staked ETH. USDC is the main stablecoin on Arbitrum.

Motivation:

One of Balancer's near term strategic objectives is to attract more yield bearing liquidity. The launch of wstETH on Arbitrum presents a huge opportunity to make Balancer the main liquidity destination for wstETH. Adding this wstETH/USDC pool will help generate additional trading activity, with the goal of encouraging other projects to also pair against wstETH.

Specifications:

1. Governance: Find more information about governance on Lido's forum.

2. Oracles: This pool relies on a rate provider for wstETH which the Orb Collective integrations team graciously deployed. See here.

3. Audits: See here.

4. Centralization vectors: See here for information on this.

5. Market History: See here.

6. Value: Balancer will earn the protocol fee on wstETH yield. We'll migrate this pool to wstETH/bbaUSD as soon as that's feasible. In the interim, the additional trading activity for wstETH this pool will generate will help make wstETH liquidity overall more profitable for Balancer. Yield fees plus swap fees is the best of both worlds.

Link to pool Link to gauge: 0x87ae77A8270F223656D9dC40AD51aabfAB424b30