Add boolean property to match the Datalabels color with the corresponding line/bar color

[bogdanblunt]

Feature Proposal
Currently, the data label's color is black and it can be changed to any fixed color.
Chartjs doesn't have a property though, to match the color of the dataset line/bar.

Possible Implementation
There are a few suggestions on the internet that currently work as workarounds only for bar. It should be possible either to match the data set colors with the datalabels', or to have access to the data[dataIndex]'s color.