feat: add AREA_CODE high performance geocoding

[joaquimds]

Part of the work required for the data pipeline V2: https://linear.app/commonknowledge/issue/MAP-973/planning-for-data-import-pipeline-v2

This adds a new Geocoder: AREA_CODE_GEOCODER_V2. To enable it, the geocoding config must have only one element, with the "type" set to "area_code".

This Geocoder uses dataloaders to ensure maximum parallelisation.

To Test

Add an AreaData source, where each row is identified to an area by code. Set up the geocoding_config to look something like:

  "type": "AREA",
  "components": [
    {
      "type": "area_code",
      "field": "oa21cd",
      "value": "",
      "metadata": {
        "lih_area_type__code": "OA21"
      }
    }
  ]
}```

Then run the import on the data source.

[janbaykara]

Nice, thanks for adding tests for this.

[janbaykara]

Do these need to be = dict() and = list() for immutability's sake?

[joaquimds]

I don't think changing them to dict() and list() would fix the immutability issue, but I think simply removing the default values works – the factory sets them to fresh {} and [] on class creation.

[sentry-io]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ OperationalError: the connection is closed hub.tasks in wrapper View Issue

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