[Feature] Add EIA Daily Spot Prices Data via FRED

[deeleeramone]

1. Why?:

   • To start building within the commodity module.
   • Quick win by curating some FRED series IDs.

2. What?:

   • New endpoint: obb.commodity.spot_prices
   • Adds daily time series data from the EIA spot prices API via FRED, and includes the metadata.
     • The list of commodities is fixed, added "commodity" as a provider parameter to allow variations between providers (future). Choices are:
       • "wti",
       • "brent",
       • "natural_gas",
       • "jet_fuel",
       • "propane",
       • "heating_oil",
       • "diesel_gulf_coast",
       • "diesel_ny_harbor",
       • "diesel_la",
       • "gasoline_ny_harbor",
       • "gasoline_gulf_coast",
       • "rbob",
       • "all"
   • The lbma_fixing endpoint from Nasdaq DataLink appears to be dead, commented out the fetcher and skipped those tests.

3. Impact:

   • openbb-commodity will populate with a function without installing any extras.

4. Testing Done:

   • Integration/unit