PR summary

Closes #10767

This allows for specific control of where the ticks and axis labels are positioned for 3D plots. This is robust to rotating the plots.

There is some refactoring work done here to break out drawing different elements into functions to enable the change, and it made me realize how much axis3d needs some work. Would like to get these upper/lower axes independently customizable, but for now this is a step in the right direction even if it doesn't solve everything.

import matplotlib.pyplot as plt
positions = ['default', 'upper', 'lower', 'both', 'none']
fig, axs = plt.subplots(1, 5, subplot_kw={'projection': '3d'})
for ax, pos in zip(axs.flatten(), positions):
    for axis in ax.xaxis, ax.yaxis, ax.zaxis:
        axis.set_label_position(pos)
        axis.set_ticks_position(pos)
    ax.set(xlabel='x', ylabel='y', zlabel='z', title=pos)

PR checklist

• "closes #0000" is in the body of the PR description to link the related issue
• new and changed code is tested
• Plotting related features are demonstrated in an example
• New Features and API Changes are noted with a directive and release note
• Documentation complies with general and docstring guidelines