feat: integrate Chainlink and Pyth price feeds for ynETHx:ETH

[matthiasmatt]

This pull request introduces support for Chainlink and Pyth price feeds for the ynETHx:ETH pair and enables aggregation of ynETH:USD pricing by combining these feeds. It also adds the Pyth Network as a new data source, updates the configuration and documentation to reflect these changes, and enhances testing to ensure the new features work as expected.

New Data Sources and Feed Integrations:

• Added support for Chainlink and Pyth feeds for ynETHx:ETH, including configuration for the Base network and contract address in chainlink.go and symbol mapping in config.go. [1] [2] [3]
• Introduced the Pyth Network as a new price source, with a full implementation (pyth.go), integration into the source registry (sources.go), and symbol mapping for ynethx:eth and eth:usd. [1] [2] [3]

Aggregate Price Calculation:

• Implemented logic in AggregatePriceProvider to compute the yneth:usd price by multiplying ynethx:eth with the best available eth:usd (or fallback to ueth:uusd), ensuring robust aggregation.

Configuration and Documentation Updates:

• Updated README.md to document the new Pyth data source, its configuration, and the new environment variables for the Base network.
• Updated CHANGELOG.md to reflect the addition of Chainlink and Pyth feeds and the aggregate ynETH:USD pricing.

Testing Enhancements:

• Added comprehensive tests for the new Pyth source (pyth_test.go), extended aggregate price provider tests to cover the new aggregation logic and fallbacks, and updated Chainlink tests to include the new ynETHx/ETH feed. [1] [2] [3]
• Added a stub price provider for easier testing of aggregation logic and improved test robustness by skipping unavailable prices instead of failing. [1] [2]

Ethereum Network Support:

• Added support for the Base network in Ethereum connection utilities, including configuration, connection logic, and tests. [1] [2] [3]

These changes collectively enhance the system’s ability to source and aggregate prices for new assets, improve configurability, and ensure reliability through robust testing.

[matthiasmatt]

Tested on localnet:

❯ nibid q oracle exchange-rates| jq .
{
  "exchange_rates": [
    {
      "pair": "b2btc:btc",
      "exchange_rate": "1.000000000000000000"
    },
    {
      "pair": "eth:usd",
      "exchange_rate": "3202.390000000000000000"
    },
    {
      "pair": "susda:usda",
      "exchange_rate": "1.091440110782436700"
    },
    {
      "pair": "uatom:uusd",
      "exchange_rate": "2.845000000000000000"
    },
    {
      "pair": "ubtc:uusd",
      "exchange_rate": "95759.100000000000000000"
    },
    {
      "pair": "ueth:uusd",
      "exchange_rate": "3204.240000000000000000"
    },
    {
      "pair": "unibi:uusd",
      "exchange_rate": "0.013624000000000000"
    },
    {
      "pair": "usda:usd",
      "exchange_rate": "0.990928816247482200"
    },
    {
      "pair": "usol:uusd",
      "exchange_rate": "142.130000000000000000"
    },
    {
      "pair": "ustnibi:unibi",
      "exchange_rate": "1.384400431535055300"
    },
    {
      "pair": "uusdc:uusd",
      "exchange_rate": "1.000600000000000000"
    },
    {
      "pair": "uusdt:uusd",
      "exchange_rate": "1.001700000000000000"
    },
    {
      "pair": "ynethx:eth",
      "exchange_rate": "1.062980920000000000"
    }
  ]
}