Time series example showing the need for XYLineData

[escay]

Not really a pull request, but an example of a Time series chart where I need support for XYDataSet.
Unit test shows working example.

Question is: could support for XYDataPoint be supported in LineData?
Like I did in this example where I used:

        XYLineChart chart = new XYLineChart(new XYLineData()
                .addDataset(new XYLineDataSet()
                        .addData(new XYDataPoint(1699457269877L, 20))
                        .addData(new XYDataPoint(1700047109694L, 20))

This is a variant of Time Series:
https://www.chartjs.org/docs/latest/axes/cartesian/time.html
x-axis date is replaced with epoch time like 1699457269877L.

where gaps are possible in the timeseries and different intervals might occur, therefor not using equidistant spread from:
https://www.chartjs.org/docs/latest/axes/cartesian/timeseries.html