Add support for OpenAPI additionalProperties

[isc-tstolker]

The API I try to call has the following definition:

      "CheckHealthResponse":{
        "required":[
          "details",
          "status"
        ],
        "properties":{
          "status":{
            "type":"string",
            "description":"Overall status derived from performed health checks. Values are \"UP\", \"DOWN\" and \"UNKNOWN\"."
          },
          "details":{
            "type":"object",
            "additionalProperties":{
              "$ref":"#/components/schemas/HealthCheckResult"
            },
            "description":"Map of the performed health checks and their results."
          }
        }
      },
      "HealthCheckResult":{
        "required":[
          "status"
        ],
        "properties":{
          "status":{
            "type":"string",
            "description":"Status of the health check. Values are \"UP\", \"DOWN\" and \"UNKNOWN\"."
          },
          "details":{
            "description":"Details of the health check result."
          }
        }
      }

A typical response that matches this is:

{
    "status": "UP",
    "details": {
        "crypto.filesystem": {
            "status": "UP"
        },
        "network.auth_config": {
            "status": "UP",
            "details": "no node DID"
        },
        "pki.crl": {
            "status": "UP"
        }
    }
}

So additionalProperties can be translated to a list of objects that each have a name and the object that is in de definition.
This part is currently missing in the model generation and not populated in the LoadFromResponse() method

[isc-tstolker]

I was able to fix this in my custom code by defining the details Property as Array of HealthCheckResult.
I plan to submit a PR for that

/// Map of the performed health checks and their results.
/// * This property is required.
Property details As array Of Nuts.Api.Monitoring.model.HealthCheckResult;

[isc-tstolker]

Has been fixed now