[Feature] Support axis.axisLabel.rotate: 'auto'

[viking7982]

What problem does this feature solve?

When we have axisLabel.interval: 0, we need to set axisLabel.rotate to prevent overlap. The rotation angel usually depends on the element width and number of the labels. Now we need to calculate the rotation manually. It would be more convinient if it could be calculated automatically.

What does the proposed API look like?

xAxis.axisLabel.rotate: 'auto'
yYxis.axisLabel.rotate: 'auto'

or

xAxis.axisLabel.rotate: (labels, dom) => {} // or some other params