Feature Request: Allow Embedding of elevation and profile REST API

[cymed]

As an addition to referring to a raster in elevation_dataset, it would be practical to be able to access elevation and profile data in the elevation config through REST APIs by extending the qwc-elevation-service.json

"config": {
  "title": "Config options",
  "type": "object",
  "properties": {
    "elevation_dataset": {
      "description": "Elevation dataset (file or URL). Example: https://data.sourcepole.com/srtm_1km_3857.tif",
      "type": "string"
    },
    "height_dataset": {
      "description": "Height dataset (file or URL). Example: https://api3.geo.admin.ch/rest/services/height",
      "type": "string"
    },
    "height_epsg": {
      "description": "EPSG of Height dataset (file or URL). Example: 4326",
      "type": "integer"
    },
    "profile_dataset": {
      "description": "Elevation dataset (file or URL). Example: https://api3.geo.admin.ch/rest/services/profile.json",
      "type": "string"
    },
    "profile_epsg": {
      "description": "EPSG of Profile dataset . Example: 4326",
      "type": "integer"
    },
  },
 "oneOf": [
   {
      "required": [
      "elevation_dataset"
      ]
  },
  {
     "required": [
       "height_dataset",
       "height_epsg",
       "profile_dataset",
       "profile_epsg"
     ]
   }
 ]