Add GET endpoints to load municipality data via the API

[Greenheart]

This allows us to load all data from the same place.

If we add the municipality data to the API, we could get better OpenAPI docs which would make it easier to get AI:s to generate frontend code using the expected data.

This would also make it easier for others outside of Klimatkollen to use the open datasets that we've compiled and processed.

Initial tasks

• GET /municipalities - list all climate-data.json
• GET /municipalities/:municipalitySlug (or ID) - details for specific municipality

Implementation ideas

• Add https://github.com/Klimatbyran/klimatkollen/blob/staging/data/output/climate-data.json to garbo
• Create a municipalityService which supports getMunicipalities() and getMunicipality(name: string)
• In the municipalityService, load climate-data.json and keep a Map in memory to allow returning company data quickly.
• Implement the cache() plugin to make the client save responses.
• Generate zod schemas based on the JSON data, for example with https://app.quicktype.io/. Use these both to parse the incoming data from the Python data pipeline when garbo starts, to ensure we get the expected data format. Also define the same schemas for the API endpoints response schemas. This will also add this to the API documentation.