OIP 35 Add wETH to risk free free value of treasury assets

To add wETH to risk-free value of treasury assets. Out of the total amount of treasury assets wETH would maintain a 2.5% stake out of 100%. e.g 100 million in risk-free value of treasury assets, wETH is worth approx 2.5 million. Since wETH has a floating price, if the price were to drop, more wETH would be added to maintain the 2.5% and if the price raises, no more wETH would be added until enough dai and frax are added so that wETH share of the treasury is back to 2.5%

This will protect the risk-free value of treasury assets from relying heavily on dai and its inflation. By adding more crypto assets to the backing of OHM we can further decentralize the protocol as we will not need to rely on USD-backed stable coins. (all dollar values above are is USD)