Show all points for date on hovering graph

[macobo]

Is your feature request related to a problem?

Currently insights graphs work well with 1-2 data points. However with more things start to be hard to digest:

1. Labels become hard to read (related PR Add event (sum of event_property) to event labels on graphs #2583)
2. Colors are hard to differentiate
3. Hovering the chart highlights only the closest point (x + y dimensions)

Example:

(note there are 3 different lines here)

Describe the solution you'd like

When moving the mouse across the chart highlight the closest date (x-coordinate) and show labels for all entries on that date.

Describe alternatives you've considered

Hovering all data points one-by-one. This is hard when the metrics can be of different scale.

Additional context

Thank you for your feature request – we love each and every one!

[macobo]

Fixed by #2600