Update stage out task to read STAC items from STAC catalog

[ngachung]

Instead of reading child links from the STAC catalog, read item links.

{
  "type": "Catalog",
  "id": "NA",
  "stac_version": "1.0.0",
  "description": "NA",
  "links": [
    {
      "rel": "root",
      "href": "./catalog.json",
      "type": "application/json"
    },
    {
      "rel": "item",
      "href": "./SNDR.SS1330.CHIRP.20230101T0000.m06.g001.L1_J1.std.v02_48.G.200101070318_REBIN.nc.stac.json",
      "type": "application/json"
    },
    {
      "rel": "item",
      "href": "./SNDR.SS1330.CHIRP.20230101T0006.m06.g002.L1_J1.std.v02_48.G.200101070318_REBIN.nc.stac.json",
      "type": "application/json"
    }
  ],
  "stac_extensions": []
}

[mcduffie]

Confirmed working with unity-app-generator and unity-example-application