feat: return API and scanner versions in the json inventory

[demeringo]

Closes #265 by adding metadata to the inventory output in json format.

{
  "metadata": {
    "estimation_date": "2024-12-14T22:47:25.783194010Z",
    "description": "Estimation using Boavizta API",
    "cloud_scanner_version": "3.2.0",
    "boavizta_api_version": "1.3.6",
    "execution_statistics": {
      "inventory_duration": {
        "secs": 0,
        "nanos": 296360816
      },
      "impact_estimation_duration": {
        "secs": 0,
        "nanos": 1937
      },
      "total_duration": {
        "secs": 0,
        "nanos": 296362753
      }
    }
  },
  "impacting_resources": []
}

[demeringo]

@jnioche @damienfernandes I want to highlight that it slightly modifies the format of the json output for the estimations (Not the format of the data itselft but it adds a metadata section in the output).

No changes on the metrics output. If implemented later it will be tracked in #266.