Add GetFeatureInfoExtended support

[pomadchin]

Overview

This PR adds the GetFeatureInfoExtended endpoint, which is a bulk version of the GetFeatureInfo endpoint

Checklist

• [x] Docker image
• [x] Description of PR is in an appropriate section of the CHANGELOG and grouped with similar changes if possible

Demo

Request

• endpoint: POST http://localhost:9000/?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetFeatureInfoExtended

 {
 "version" : "1.3.0",
  "layers": [
    "stac-lc8-red"
  ],
  "multiPoint": {
    "type": "MultiPoint",
    "coordinates": [
      [
        -100.03809180392743,
        38.91831768776311
      ],
      [
        -76.48175638801354,
        40.37241246652323
      ],
      [
        -77.18803099483988,
        38.75213542733338
      ],
      [
        -74.19675030710478,
        39.04295438308541
      ]
    ]
  },
  "time": "2017-05-21T00:00:00Z/2019-07-08T00:00:00Z"
}

Response

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          -100.03809180392743,
          38.91831768776311
        ]
      },
      "properties": {
        "band-0-pixel-value": 9865
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          -76.48175638801354,
          40.37241246652323
        ]
      },
      "properties": {
        "band-0-pixel-value": 7439
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          -77.18803099483988,
          38.75213542733338
        ]
      },
      "properties": {
        "band-0-pixel-value": 8530
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          -74.19675030710478,
          39.04295438308541
        ]
      },
      "properties": {
        "band-0-pixel-value": 9174
      }
    }
  ]
}