Add support for PYTH oracles

[yabirgb]

PYTH is a competitor to ChainLink and provides price feeds for several crypto assets. In addition it provides fees for stocks that can be used in the future.

There is an API that can be used to query all the available fees at: https://hermes.pyth.network/v2/price_feeds?asset_type=crypto
Documented at: https://hermes.pyth.network/docs/#/rest/price_feeds_metadata

They provide APIs to query them but the great thing about those fees is that they can be queried on chain using RPC calls. This allows us to avoid rate limits theoretically.

Documentation available at: https://docs.pyth.network/price-feeds/price-feeds

how to query

For example for the ethereum contract (https://etherscan.io/address/0x4305fb66699c3b2702d4d05cf36551390a4c69c6#readProxyContract) we can call the method queryPriceFeed with the uniswap feed ID 0x78d185a741d07edb3412b09008b7c5cfb9bbbd7d568bf00ba737b456ba171501

Properties

• crypto oracle
• stock oracle
• current price
• historical price (using archive nodes)