Change outside legend API

[josephmure]

What is the idea?

setLegendCorner --> setLegendLocation

Takes 2 arguments : a point with the matplotlib "bbox_anchor" + a string with the legend position within the box.

Why is this needed?

To make the API more user-friendly and more consistent with Matplotlib.

Additional Context

No response

[jschueller]

setLegendLocation would be too close to setLegendPosition I propose to keep setLegendCorner but add an optional argument to setLegendPosition bool outside=off, then the anchor could be automatically set to the corresponging coordinates but setLegendAnchor would have been a better name for setLegendCorner