Add includeInvisible option to interaction to manage negative spacing options

[stockiNail]

Fix #146.

This PR is also raising the minimum version of CHART.JS to 3.8.0, where includeInvisible option has been added to interaction.

[stockiNail]

@kurkle I have a doubt if it's a breaking change, due to new minimum needed CHART.JS version.

[kurkle]

This still bothers me a little, because those rects are visible. I think in Chart.js interactions it's assumed that x/y are the center point of the element, which is not always the case.

We should either fix Chart.js (could require using getCenterPoint, which would be bad for performance) or update the mode so that x/y in parsed data are center points of the rects.

[stockiNail]

This still bothers me a little, because those rects are visible. I think in Chart.js interactions it's assumed that x/y are the center point of the element, which is not always the case.

I think CHART.JS is checking that whole rect (or shape) is in the chart area. Maybe it could check if a part of the element is in area to go on, instead of whole element.