Convert Trends.Earth JSON Outputs to STAC Items

[Samweli]

Part of #825

Update Trends.Earth's JSON output generation to ensure compatibility with the STAC Item specification. Each dataset instance should be wrapped in a STAC Item, with relevant metadata. Also make sure to take into account the updates discussed in the parent issues for the JSON outputs.

All the STAC Items should adhere to the standards, e.g each item should have a valid spatial (bbox), temporal (datetime), and additional properties if present.

The final STAC items should be validated using the stac-validator tool.

Sample JSON output converted to a STAC Item

{
  "stac_version": "1.0.0",
  "stac_extensions": ["https://stac-extensions.github.io/item-assets/v1.0.0/schema.json"],
  "id": "country_sdg_15_3_1",
  "type": "Feature",
  "geometry": {
    "type": "Polygon",
    "coordinates": [[
      [10.000, 5.000], [20.000, 5.000],
      [20.000, 15.000], [10.000, 15.000],
      [10.000, 5.000]
    ]]
  },
  "bbox": [10.000, 5.000, 20.000, 15.000],
  "properties": {
    "title": "SDG 15.3.1 Data for country",
    "description": "Land degradation monitoring results for country.",
    "country": "country",
    "data_source": "Trends.Earth LPD",
    "datetime": "2025-02-04T00:00:00Z"
  },
  "assets": {
    "jrc_data": {
      "href": "countries/country/assets/sdg-15-3-1-country-jrc.json",
      "title": "JRC LPD Data for country",
      "type": "application/json",
      "roles": ["data"]
    },
    "trends_earth_data": {
      "href": "countries/country/assets/sdg-15-3-1-country-trends.json",
      "title": "Trends.Earth LPD Data for country",
      "type": "application/json",
      "roles": ["data"]
    },
    "summary_excel": {
      "href": "countries/country/assets/sdg-15-3-1-summary.xlsx",
      "title": "Summary XLSX",
      "type": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
      "roles": ["metadata"]
    },
    "summary_vrt": {
      "href": "countries/country/assets/sdg-15-3-1-summary.vrt",
      "title": "Summary VRT",
      "type": "application/x-vrt",
      "roles": ["metadata"]
    },
    "baseline_tif": {
      "href": "countries/country/assets/sdg-15-3-1-baseline.tif",
      "title": "Baseline Raster",
      "type": "image/tiff",
      "roles": ["data"]
    },
    "progress_tif": {
      "href": "countries/country/assets/sdg-15-3-1-progress.tif",
      "title": "Progress Raster",
      "type": "image/tiff",
      "roles": ["data"]
    }
  },
  "links": [
    {
      "rel": "collection",
      "href": "countries/country/country.json",
      "type": "application/json",
      "title": "SDG 15.3.1 Collection for country"
    },
    {
      "rel": "root",
      "href": "../catalog.json",
      "type": "application/json",
      "title": "Root STAC Catalog"
    }
  ]
}