UMIP 85 -Add R3_10H_TWAP and R3_30D_GM as supported price identifiers

This UMIP will reference a synthetic token to be created with this price identifier.
This token will be referred to as ‘R3’ (Rai Redemption Rate) and will represent the token that tracks these identifiers.

The DVM should support price requests for the R3_10H_TWAP and R3_30D_GM price indices.

The DVM should support requests for a price that resolves to either the 30 day geometric mean (R3_30D_GM) or
a 10-hour Time-Weighted Average Price (R3_10H_TWAP) of RAI redemption rate coefficient APR.