feat(tooltip): Enhance tooltip.position passing curr pos

[netil]

Issue

#2267

Details

Pass position object argument to tooltip.position callback
to facilitate position value control.

tooltip: {
     position: function(data, width, height, element, pos) {
         // data: [{x, index, id, name, value}, ...]
         // width: Tooltip width
         // height: Tooltip height
         // element: Tooltip event bound element
         // pos: {
         //   x: Current mouse event x position,
         //   y: Current mouse event y position,
         //   xAxis: Current x Axis position
         // }
         return {top: 0, left: 0}
     },
}