Rest Swagger - support `parameters` applicable for all the operations under `path`

[hellosnow]

Currently, docfx rest swagger support parameters directly under get, put operation etc. But according Swagger paths schema, paths should support parameters that are applicable for all the operations described under each path.

{
  "paths": {
    "/test": {
      "parameters": [{
        "$ref": "#/parameters/A"
      }],
      "get": {
        "operationId": "B",
        "parameters": [{
          "name": "kind",
          "in": "path",
          "required": true,
          "type": "string"
        }]
      }
    }
  }
}