Support XYDataPoint support in LineDataSet

[escay]

Checklist

• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have taken the time to fill in all the required details. I understand that the feature request will be dismissed otherwise.
• This issue contains only one feature request/enhancement.

Description

Support XYDataPoint support in LineDataSet to be able to model a ChartJs graph like:

https://jsfiddle.net/escay/y9j3x5cf/6/

for Time series with non equidistant date values. In pull request #488 you can see an example of how it might work. Although I am not sure if introducing new XYLineDataSet classes would be desired as a solution.

Relevant ChartJs documentation: https://www.chartjs.org/docs/latest/axes/cartesian/time.html where line dataset can contain XYDataPoints:

let chart = new Chart(ctx, {
    type: 'line',
    data: {
        datasets: [{
            data: [{
                x: '2021-11-06 23:39:30',
                y: 50
            }, {
                x: '2021-11-07 01:00:28',
                y: 60
            }, {
                x: '2021-11-07 09:00:28',
                y: 20
            }]
        }],
    },

Full example of the goal, but using epoch timestamps to let ChartJs do the timezone conversion of the x axis:

{
        "data": {
            "datasets": [
                {
                    "backgroundColor": "rgba(40, 180, 99, 0.3)",
                    "borderColor": "rgb(40, 180, 99)",
                    "borderWidth": 1,
                    "data": [
                        {
                            "x": 1699457269877,
                            "y": 20
                        },
                        {
                            "x": 1700047109694,
                            "y": 20
                        }
                    ],
                    "hidden": false,
                    "label": "Device Id: 524967 Register: A- total Wh",
                },
                {
                    "backgroundColor": "rgba(218, 117, 255, 0.3)",
                    "borderColor": "rgb(218, 117, 255)",
                    "borderWidth": 1,
                    "data": [
                        {
                            "x": 1699457267847,
                            "y": 10
                        },
                        {
                            "x": 1700047108397,
                            "y": 234
                        }
                    ],
                    "hidden": false,
                    "label": "Device Id: 524967 Register: A+ total Wh",
                }
            ]
        },
        "options": {
            "plugins": {
                "legend": {
                    "display": true,
                    "fullWidth": true,
                    "position": "top",
                    "reverse": false,
                    "rtl": false
                },
                "title": {
                    "display": true,
                    "text": "Values from the meter"
                }
            },
            "scales": {
                "x": {
                    "beginAtZero": false,
                    "offset": true,
                    "reverse": false,
                    "stacked": true,
                    "ticks": {
                        "autoSkip": true,
                        "maxRotation": 0,
                        "minRotation": 0,
                        "mirror": false,
                        "source": "data"
                    },
                    "time": {
                        "displayFormats": {
                            "minute": "dd.LL T"
                        },
                        "round": "minute",
                        "stepSize": "60",
                        "unit": "minute"
                    },
                    "type": "time"
                },
                "y": {
                    "beginAtZero": false,
                    "offset": false,
                    "reverse": false,
                    "stacked": true,
                    "ticks": {
                        "autoSkip": true,
                        "mirror": false
                    }
                }
            },
            "showLine": true,
            "spanGaps": false
        },
        "type": "line"
    }

Additional information

No response