enable color by timedelta in Plotly Express

When you domain is time series data, you sooner or later have to plot data of the Timedelta type. It would be nice to be able to understand what I am looking at when plotting, and coloring by, such data, which is hard when it is interpreted as an int in both hover text and color bar tick text.

Similar to #2450, but covering the timedelta data type, rather than datetime.

See also #799 and #801 for similar requests for the x and y axes.

首先查看 #2450 中相關的 datetime 請求，以及 #799 和 #801 中類似的座標軸請求，然後追蹤 Plotly Express 如何處理用於懸停文字和色彩尺度的 Timedelta 值。完成的標準是：timedelta 色彩值在懸停文字和色彩條刻度標籤中以有意義的形式呈現，而不是顯示為整數。