Add common alias perspective (p) for plotting 3D illustrations

[weiji14]

Description of proposed changes

Used to select a perspective view by setting the azimuth and elevation angle of the viewpoint. See https://docs.generic-mapping-tools.org/6.1/gmt.html#perspective-full.

Live documentation preview for this PR/branch is at https://pygmt-git-common-aliases-p.gmt.vercel.app/api/generated/pygmt.Figure.plot.html

Note that the 'perspective' name follows the upstream GMT long option name convention at https://github.com/GenericMappingTools/gmt/blob/88421f9f8fe9759692302905268f4036b287adcb/src/gmt_init.c#L408

This PR will be a part of #620 too.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

[weiji14]

Cool, thanks for reviewing this series of 'common alias' PRs @seisman! This should be one of the last important ones at https://docs.generic-mapping-tools.org/6.1/std-opts.html to be handled. There's still -c but that will be done in the subplot wrapper.