eIP 22: Move newly activated assets price oracles to Chainlink, move LRC price oracle back to Uniswap TWAP

Motivation

This proposal is a follow-up of the eIP 18 that proposed to move all asset price oracles to Chainlink where available. Since the proposal was voted and implemented, a few new markets have been activated on Euler for which Chainlink oracles can be used. In that regard, eIP 18 risk assessment and analysis still hold.

Also, one of the price feeds has been scheduled to be deprecated on Oct 12th 2022, hence to keep the market secure, its oracle should be moved back to Uniswap v3 TWAP.

Implementation

The following assets will switch to Chainlink should eIP 22 pass:

1. FRAX
2. FXS
3. COMP

The following assets will switch back to Uniswap v3 TWAP oracle should eIP 22 pass:

1. LRC, 0.3% pool will be used

Conclusion

These changes will switch the price oracle for newly activated markets where available. This is intended to increase the security of these markets and lower overall systemic risk on the protocol post Merge. Additionally, the market for which Chainlink price feed will be deprecated will be switched back to the Uniswap v3 TWAP oracle that was used for it pre-eIP 18.