Allow selection of single series from tooltip

[nickofthyme]

Is your feature request related to a problem? Please describe.
Having a click listener that returns single desired value/point/series

Describe the solution you'd like

From discussion on #548

A static tooltip to allow the user to select a series within a given proximity.

If consumers only want a single point passed back to them, they could tell the chart to allow "affixing" the tooltip when the user clicks on a point. This will then allow the exact point in the tooltip to be clickable and sent back to the consumer. (#548 (comment))

Describe alternatives you've considered
Handle multiple series form the event

Checklist

• this request is checked against already exist requests
• every related Kibana issue is listed under Kibana Cross Issues list
• kibana cross issue tag is associated to the issue if any kibana cross issue is present

[markov00]

Done in #1782