YXChart: allow to specify axis' relative position

In XYChart, currently X axis sits on the bottom of the chart and Y sits on the left side of the chart.
We need a way to be able to specify on which side of the chart the axis are.
Each axis needs to be configured independantly from each other.

An API should be added to allow to specify the location of the axis:
AxisLocation.LEADING : if set X axis is on top, if set Y axis is on left (assuming left->right is the default as specified by current locale)
AxisLocation.TRAILING : if set X axis in on bottom, if set Y axis is on right.
AxisLocation.NONE : axis is not visible and no space is reserved for it when computing the chart area (this would allow the support of undecorated charts). The chart's grid should still be visible if configured to appear.

Using this values, current default settings are:
AxisLocation.TRAILING for X axis (it sits at bottom)
AxisLocation.LEADING for Y axis (it sits on left)

If this is implemented, axis rendering needs to be updated to support alternate label, tick label and tick location as they vary depending of the location of the axis.