Implement station value renderer for 3 situations: "at", "from" and "to"

[grigasp]

Example rule to use the renderer:

{
  "ruleType": "ContentModifier",
  "class": {
    "schemaName": "CivilPhysical",
    "className": "Course"
  },
  "calculatedProperties": [{
    "label": "Station Value (at)",
    "renderer": {
      "rendererName": "AtStation"
    },
    "value": "this.ECInstanceId"
  }, {
    "label": "Station Value (from)",
    "renderer": {
      "rendererName": "FromStation"
    },
    "value": "this.ECInstanceId"
  }, {
    "label": "Station Value (to)",
    "renderer": {
      "rendererName": "ToStation"
    },
    "value": "this.ECInstanceId"
  }]
}