Add OETH/OUSD to Flashstake

[sumpg41]

Flashstake is a Pendle competitor that already supports stETH and rETH. Adding OETH and OUSD (or the wrapped versions) should be relatively low effort. Apparently the constructor of the time vault can call the rebaseOptIn() function.

"Do you have any developers who can help write smart contracts for a flashstake integration? We can onboard them to show them how. The main logic requirement is knowing how to separate yield from principal." - Steve from FS

Docs: https://docs.flashstake.io/

Existing FS yield strategies: https://docs.flashstake.io/time-vault-strategies-tvs/time-vaults-database

FS stETH time vault: https://etherscan.io/address/0xB8C60a5C9d73C0406FF279C65E31496a40F0dc5a#code%23F1%23L1