Plotly: subplots in figure (Part 1)

In Matplotlib, subplot can be easily pulled out as following:

However, matplotlib is not quite smart to handle the axis ticks rotation (sometimes they collapse together and hard to visualize), and this could be troublesome for some automatic visualization process. In general, I found plotly offer a better automated layout.

The way subplots in plotly and matplotlib are conceptually different on:
1. (matplotlib) figure --- axes --- artist, so that one figure can contain multiple axes, and each axes has their own set of artist. For example, legend is an artist, and each axes could have its own legend
2. (plotly) the main component in a figure is "data" and "layout", the way subplot works is to create multiple data, put into different axis. This is still one big figure. each subplot is just different axis(x,y) located on different locations in this big Figure. 

Here is a few action