Add support for window expressions

[EpsilonPrime]

What happens?
Window functions are not yet supported. Attached is a sample plan that uses the row_number window function in case it helps. I did notice that the substrait-validator does not have support for window functions so we will look into addressing that.

To Reproduce
The following snippet uses the users.parquet dataset from the spark-substrait-gateway but it's only here as a sample.

{
  "extensionUris": [
    {
      "extensionUriAnchor": 1,
      "uri": "/functions_arithmetic.yaml"
    }
  ],
  "extensions": [
    {
      "extensionFunction": {
        "extensionUriReference": 1,
        "functionAnchor": 1,
        "name": "row_number"
      }
    }
  ],
  "relations": [
    {
      "root": {
        "input": {
          "project": {
            "common": {
              "emit": {
                "outputMapping": [
                  3,
                  4,
                  5,
                  6
                ]
              }
            },
            "input": {
              "read": {
                "common": {
                  "direct": {}
                },
                "baseSchema": {
                  "names": [
                    "user_id",
                    "name",
                    "paid_for_service"
                  ],
                  "struct": {
                    "types": [
                      {
                        "string": {
                          "nullability": "NULLABILITY_REQUIRED"
                        }
                      },
                      {
                        "string": {
                          "nullability": "NULLABILITY_REQUIRED"
                        }
                      },
                      {
                        "bool": {
                          "nullability": "NULLABILITY_REQUIRED"
                        }
                      }
                    ],
                    "nullability": "NULLABILITY_REQUIRED"
                  }
                },
                "namedTable": {
                  "names": [
                    "users"
                  ]
                }
              }
            },
            "expressions": [
              {
                "selection": {
                  "directReference": {
                    "structField": {}
                  },
                  "rootReference": {}
                }
              },
              {
                "selection": {
                  "directReference": {
                    "structField": {
                      "field": 1
                    }
                  },
                  "rootReference": {}
                }
              },
              {
                "selection": {
                  "directReference": {
                    "structField": {
                      "field": 2
                    }
                  },
                  "rootReference": {}
                }
              },
              {
                "windowFunction": {
                  "functionReference": 1,
                  "sorts": [
                    {
                      "expr": {
                        "selection": {
                          "directReference": {
                            "structField": {
                              "field": 1
                            }
                          },
                          "rootReference": {}
                        }
                      },
                      "direction": "SORT_DIRECTION_ASC_NULLS_FIRST"
                    }
                  ],
                  "upperBound": {
                    "unbounded": {}
                  },
                  "lowerBound": {
                    "unbounded": {}
                  },
                  "outputType": {
                    "i64": {
                      "nullability": "NULLABILITY_REQUIRED"
                    }
                  },
                  "invocation": 3
                }
              }
            ]
          }
        },
        "names": [
          "user_id",
          "name",
          "paid_for_service",
          "row_number"
        ]
      }
    }
  ],
  "version": {
    "minorNumber": 52,
    "producer": "spark-substrait-gateway"
  }
}