Add storage for Bifrost LST oracles

[green-jay]

Bifrost parachain (id 2030) will regularly push their prices to us via XCM (in a format we specify) and so we need to set up a place to store them.

emaOracle pallet can be used to store these values via a new extrinsic public fn emaOracle.update_bifrost_oracle( asset_a: Location, asset_b: Location: price: (u128, u128) where locations are defined from Hydration perspective and values to determine price are sourced from vTokenMinting.tokenPool and tokens.TotalIssuance storages on Bifrost parachain.

Permission to set/store these oracles should be set for Bifrost sibling account 7LCt6dFs6sraSg31uKfbRH7soQ66GRb3LAkGZJ1ie3369crq.

[jak-pan]

We already support different sources.

We can use source as Bifrost

hydration-node/pallets/ema-oracle/src/lib.rs

Line 251 in ea4e622

pub fn add_oracle(origin: OriginFor<T>, source: Source, assets: (AssetId, AssetId)) -> DispatchResult {

And then we need to add manual update function which will be whitelisted to Bifrost.

We could potentially just skip the EMA part while doing the manual update and just not use it. Alternatively use it to build aggregate for security reasons.