Fix ITL JSON optional SOC observation top level keys

The current majis.itl.json.export.fmt_json is using an explicit EPS_MAPPING_OBS and EPS_MAPPING_PARAMS mapping table to identify how the output structure need to be formatted to be valid with the schema.

Unfortunately some optional parameters (like pointing_description) are not listed and ends up in the parameters section instead of the observation keys:

{
  "timeline": [
    {
      "parameters": {
        "pointing_description": "foo"
      }
    }
  ]
}

instead of:

{
  "timeline": [
    {
      "pointing_description": "foo"
    }
  ]
}

Either the list list needs to be extended, or the SOC mapping should be derived from the SOC JSON schema (preferred).