GET interaction support in Batch transactions

[andy-a-o]

Is your feature request related to a problem? Please describe.
https://www.hl7.org/fhir/STU3/http.html#2.21.0.5.2

For example, this request leads to 500 response:

{
  "type": "transaction",
  "entry": [
    {
      "request": {
        "method": "GET",
        "url": "Observation?code=http://loinc.org|3141-9&patient=Patient/1096"
      }
    },
    {
      "fullUrl": "http://localhost:5000/fhir/Observation/70",
      "resource": {
        "id": "70",
        "meta": {
          "tag": [
            {
              "system": "http://projectcrucible.org",
              "code": "testdata"
            }
          ]
        },
        "status": "final",
        "code": {
          "coding": [
            {
              "system": "http://loinc.org",
              "code": "3141-9"
            }
          ]
        },
        "subject": {
          "reference": "Patient/1096"
        },
        "valueQuantity": {
          "value": 105,
          "unit": "kg",
          "system": "http://unitsofmeasure.org"
        },
        "resourceType": "Observation"
      },
      "request": {
        "method": "PUT",
        "url": "Observation/70"
      }
    },
    {
      "fullUrl": "urn:uuid:246a78d3-dd8b-492f-bcf4-9631b1969377",
      "resource": {
        "meta": {
          "tag": [
            {
              "system": "http://projectcrucible.org",
              "code": "testdata"
            }
          ]
        },
        "status": "final",
        "code": {
          "coding": [
            {
              "system": "http://loinc.org",
              "code": "8302-2"
            }
          ]
        },
        "subject": {
          "reference": "Patient/1096"
        },
        "valueQuantity": {
          "value": 177,
          "unit": "cm",
          "system": "http://unitsofmeasure.org"
        },
        "resourceType": "Observation"
      },
      "request": {
        "method": "POST",
        "url": "Observation"
      }
    },
    {
      "request": {
        "method": "DELETE",
        "url": "Observation/73"
      }
    }
  ],
  "resourceType": "Bundle"
}

Describe the solution you'd like
GET interaction is supported as a part of batch transaction.

Failed tests
TransactionAndBatchTest (XFER4)

[kennethmyhra]

Shaved off some yaks, still some more to go.

• GET request which translates to a search should be a Bundle.type="searchset" within one (1) entry.