[Feature] Show axisLabels on X-axis from points in my data

### What problem does this feature solve?

Currently, when we plot a line chart with `option.xAxis.type="time"`, echarts automatically calculates the points which are going to be shown on X axis according to the start and end point from our series data. We have option to whether to show these points or not using some formatting tricks, but it will only show the points at the intervals calculated by echarts.

Sometimes, what happens is that there are no co-inciding points between those and time in data points.
Live Example: https://shorturl.at/djpAF
In the above case, we don't get a time label that is exactly below my data point.

I want the time axis labels to be shown directly under the data point (It doesn't matter if they are being plotted at equal interval or not).

I have tried various configurations, but could not get the desired result. Please tell me if I have missed something, else this feature could be really benificial.

### What does the proposed API look like?

`option.xAxis.showCustomPoints: true`
or something like this.

No source file or test entry point is named in the issue. Reproduce the linked live example with a time-based xAxis, then trace how ECharts calculates and formats x-axis labels; done means data-point times can be shown directly below their points without requiring equal intervals and the proposed API behavior is defined.

Written by the indexing model from the issue text.