[5.0] [FEATURE] Improve default axis style

[pissang]

Brief Information

What does this PR do?

This pull request includes optimization of the default axis style. Which includes:

1. Not shown line and tick of value axis when another axis is category or time
2. Change the color of the line, label, splitLine, splitArea.
3. Change the color of dataZoom label.
4. Change the color of axisPointer. Also, change it to dashed line.
5. Change the color of title subtext.

The whole change is to emphasize the main chart area by downplaying the axis.

Details

Before: What was the problem?

After: How is it fixed in this PR?

[echarts-bot]

Thanks for your contribution!
The community will review it ASAP. In the meanwhile, please checkout the coding standard and Wiki about How to make a pull request.

[echarts-bot]

Congratulations! Your PR has been merged. Thanks for your contribution! 👍