[V5] Feature: Add JODI World Oil & Gas Database

[deeleeramone]

This PR adds the JODI oil and gas databases.

The entire database is available from three compressed CSV files, so the first caller takes the loading cost of downloading and caching. PyArrow is used as a dependency to convert these into queryable parquet bundles on disk, which minimizes the memory load for lookups.

Endpoints

Each endpoint returns one presentation-ready view of the raw data, as a date-indexed table, with the series assessments and units in the results metadata.

obb.jodi.oil — JODI-Oil World Database (monthly, from January 2002)

• balance — one country and product; one column per flow of the JODI questionnaire (production, trade, stocks, refinery activity).
• production — one primary product; one column per reporting country.
• demand — one refined product; one column per reporting country.
• demand_by_product — one country; one column per refined product (the demand barrel).
• imports / exports — one product; one column per reporting country.
• stocks — closing stock levels of one product; one column per reporting country.

Units: kb/d, kbbl, kl, kmt, and the barrels/kmt conversion factor.

obb.jodi.gas — JODI-Gas World Database (monthly, from January 2009)

• balance — one country; one column per flow of the JODI questionnaire.
• production — one column per reporting country.
• demand — gross inland deliveries (observed or calculated); one column per reporting country.
• imports / exports — total, pipeline, or LNG; one column per reporting country.
• stocks — closing stock levels; one column per reporting country.

Units: million m3, TJ, and kmt of LNG.