make grid simplify subplots (mixed plots not working currently)

Usecase:
User should be able to draw subplots with ease by using grid option.
User has 4 diff graphs and he wants to put them together, in grid by using following option without getting into much complexity

grid: {
    rows: 2,
    columns: 2,
    pattern: "independent"
  }
}

Ease of use:
It will be great to have similat functionality like provided in python plotly where user can define rows, columns, colspan and rowspan in data. Its plain and dead easy.

from plotly.subplots import make_subplots
import plotly.graph_objects as go

fig = make_subplots(
    rows=5, cols=2,
    specs=[[{}, {"rowspan": 2}],
           [{}, None],
           [{"rowspan": 2, "colspan": 2}, None],
           [None, None],
           [{}, {}]],
    print_grid=True)

Reference:
python plotly.subplots has given functionality with much ease of use. see HERE. Same is needed for js Please

Code Pen:
https://codepen.io/mafar/pen/YzZEdLR?editors=0010

JS CODE:

var trace1 = {
  type: "bar",
  y: [2, 3, 1]
};

var trace2 = {
  r: [2, 3, 1],
  theta: [0, 45, 90],
  type: "barpolar"
};

var trace3 = {
  type: "pie",
  values: [2, 3, 1]
};

var trace4 = {
  mode: "lines",
  type: "scatter3d",
  x: [2, 3, 1],
  y: [0, 0, 0],
  z: [0.5, 1, 2]
};

var data = [trace1, trace2, trace3, trace4];

var layout = {
  grid: {
    rows: 2,
    columns: 2,
    pattern: "independent"
  }
};

Plotly.newPlot("myDiv", data, layout);

まず、Plotly.newPlot を使って bar、barpolar、pie、scatter3d の混在した例を再現し、リンク先の CodePen と比較します。既存のグリッドレイアウトの動作と Python Plotly のサブプロットリファレンスを読み、そのうえで rows、columns、独立した混在プロット、colspan、rowspan のサポートに何が必要かを定義します。手動でサブプロットを設定せずに例が動作すれば完了です。