RESTful service to delete, cancel and reschedule Export Tasks

[gunterze]

swagger.json

{
    "/monitor/export/{taskPK}": {
      "delete": {
        "tags": [
          "MONITOR-RS",
          "EXPORT-RS"
        ],
        "summary": "Delete Export Task",
        "operationId": "deleteExportTask",
        "parameters": [
          {
            "name": "taskPK",
            "in": "path",
            "description": "pk of task",
            "required": true,
            "type": "integer"
          }
        ],
        "responses": {
          "204": {
            "description": "successful operation"
          },
          "404": {
            "description": "task not found"
          },
          "default": {
            "description": "unexpected error"
          }
        }
      }
    },
    "/monitor/export/{taskPK}/cancel": {
      "post": {
        "tags": [
          "MONITOR-RS",
          "EXPORT-RS"
        ],
        "summary": "Cancel Export Task",
        "operationId": "cancelExportTask",
        "parameters": [
          {
            "name": "taskPK",
            "in": "path",
            "description": "pk of task",
            "required": true,
            "type": "integer"
          }
        ],
        "responses": {
          "204": {
            "description": "successful operation"
          },
          "404": {
            "description": "task not found"
          },
          "409": {
            "description": "tasks with status TO SCHEDULE, CANCELED, COMPLETED, WARNING or FAILED cannot be canceled"
          },
          "default": {
            "description": "unexpected error"
          }
        }
      }
    },
    "/monitor/export/{taskPK}/reschedule/{exporterID}": {
      "post": {
        "tags": [
          "MONITOR-RS",
          "EXPORT-RS"
        ],
        "summary": "Reschedule Export Task to potential different Exporter",
        "operationId": "rescheduleExportTask",
        "parameters": [
          {
            "name": "taskPK",
            "in": "path",
            "description": "pk of task",
            "required": true,
            "type": "integer"
          },
          {
            "name": "exporterID",
            "in": "path",
            "description": "Exporter ID",
            "required": true,
            "type": "string"
          }
        ],
        "responses": {
          "204": {
            "description": "successful operation"
          },
          "404": {
            "description": "task or exporter not found"
          },
          "409": {
            "description": "tasks with status SCHEDULED or IN PROCESS cannot be rescheduled"
          },
          "default": {
            "description": "unexpected error"
          }
        }
      }
    }
}

Related: #596
Requires: #594