[ENH]: quiverkey accepts transform argument directly instead of coordinates

[ZhaJiMan]

Problem

quiverkey now uses the coordinates argument to set its transform instead of using transform argument like other artists. And it only supports four coordinates: axes, figure, data and inches. When I pass transform=cbar.ax.transAxes to make the quiverky above a color bar, it will fail due to the coordinates argument (actually its _set_transform method under the hood). Another example is that when using Cartopy, I want to pass transform=ccrs.PlateCarree() to use longitude and latitude as X and Y.

I hope quiverkey to accept transform directly, which is consistent with other artists, and make the coordiantes more flexible.

Proposed solution

No response