docs: Add missing descriptions, sources, and licenses

[dsmedia]

Pull Request: Add missing descriptions, sources, and licenses to datapackage files

Objective:

Following up on the metadata infrastructure work in #634, #639, and #646, this PR adds missing description, source, and license metadata to datapackage_additions.toml. The checklist below indicates which metadata entries are missing and still need to be added. Schema entries (describing each dataset column) will be handled in a subsequent pull request.

Open Questions:

• Decide how to handle license information that cannot be determined after research, ensuring validation with frictionless standard for licenses.

Status:

The following checklist indicates the completion status of the description, sources, and licenses metadata for each dataset. A green checkmark (✅) indicates the metadata is present, a red X (❌) indicates the metadata is missing. The leading checkbox is only checked if all three types of metadata are present.

Process:
Changes are validated using scripts/build_datapackage.py, which generates machine-readable metadata describing the contents of /data/.

Legend:

• ✅ - Indicates the metadata is present
• ❌ - Indicates the metadata is missing
• [x] - Indicates all three types of metadata are present
• [ ] - Indicates one or more types of metadata are missing

Checklist:

• 7zip.png: description✅, sources✅, license✅
• airports.csv: description❌, sources❌, license❌
• annual-precip.json: description✅, sources✅, license❌
• anscombe.json: description✅, sources❌, license❌
• barley.json: description✅, sources✅, license❌
• birdstrikes.csv: description✅, sources✅, license❌
• budget.json: description✅, sources✅, license❌
• budgets.json: description❌, sources❌, license❌
• burtin.json: description✅, sources✅, license❌
• cars.json: description✅, sources✅, license❌
• co2-concentration.csv: description✅, sources✅, license❌
• countries.json: description✅, sources✅, license✅
• crimea.json: description✅, sources✅, license❌
• disasters.csv: description✅, sources✅, license❌
• driving.json: description❌, sources✅, license❌
• earthquakes.json: description✅, sources✅, license❌
• ffox.png: description✅, sources✅, license✅
• flare-dependencies.json: description❌, sources❌, license❌
• flare.json: description❌, sources❌, license❌
• flights-10k.json: description✅, sources✅, license❌
• flights-200k.arrow: description✅, sources✅, license❌
• flights-200k.json: description✅, sources✅, license❌
• flights-20k.json: description✅, sources✅, license❌
• flights-2k.json: description✅, sources✅, license❌
• flights-3m.parquet: description✅, sources✅, license❌
• flights-5k.json: description✅, sources✅, license❌
• flights-airport.csv: description✅, sources✅, license❌
• football.json: description✅, sources✅, license❌
• gapminder-health-income.csv: description✅, sources✅, license✅
• gapminder.json: description✅, sources✅, license✅
• gimp.png: description✅, sources❌, license❌
• github.csv: description✅, sources❌, license❌
• global-temp.csv: description✅, sources✅, license❌
• income.json: description❌, sources❌, license❌
• iowa-electricity.csv: description✅, sources✅, license❌
• jobs.json: description✅, sources✅, license❌
• la-riots.csv: description✅, sources✅, license❌
• londonBoroughs.json: description✅, sources✅, license❌
• londonCentroids.json: description✅, sources❌, license❌
• londonTubeLines.json: description✅, sources✅, license❌
• lookup_groups.csv: description❌, sources❌, license❌
• lookup_people.csv: description❌, sources❌, license❌
• miserables.json: description❌, sources❌, license❌
• monarchs.json: description✅, sources✅, license❌
• movies.json: description✅, sources❌, license❌
• normal-2d.json: description❌, sources❌, license❌
• obesity.json: description❌, sources❌, license❌
• ohlc.json: description✅, sources✅, license❌
• penguins.json: description✅, sources✅, license❌
• platformer-terrain.json: description✅, sources✅, license❌
• points.json: description❌, sources❌, license❌
• political-contributions.json: description✅, sources✅, license❌
• population.json: description✅, sources✅, license❌
• population_engineers_hurricanes.csv: description✅, sources✅, license❌
• seattle-weather-hourly-normals.csv: description✅, sources✅, license❌
• seattle-weather.csv: description✅, sources✅, license❌
• sp500-2000.csv: description✅, sources✅, license❌
• sp500.csv: description❌, sources❌, license❌
• stocks.csv: description❌, sources❌, license❌
• udistrict.json: description❌, sources❌, license❌
• unemployment-across-industries.json: description✅, sources✅, license❌
• unemployment.tsv: description✅, sources✅, license❌
• uniform-2d.json: description❌, sources❌, license❌
• us-10m.json: description✅, sources✅, license✅
• us-employment.csv: description✅, sources✅, license❌
• us-state-capitals.json: description❌, sources❌, license❌
• volcano.json: description✅, sources✅, license❌
• weather.csv: description✅, sources✅, license❌
• weekly-weather.json: description✅, sources❌, license❌
• wheat.json: description✅, sources✅, license❌
• windvectors.csv: description✅, sources❌, license❌
• world-110m.json: description✅sources✅license✅
• zipcodes.csv: description✅, sources✅, license✅