``boxplot`` and ``bxp`` *vert* parameter, and ``rcParams["boxplot.vertical"]``

The parameter *vert: bool* has been deprecated on `~.Axes.boxplot` and
`~.Axes.bxp`. It is replaced by *orientation: {"vertical", "horizontal"}*
for API consistency.

``rcParams["boxplot.vertical"]``, which controlled the orientation of ``boxplot``,
is deprecated without replacement.