Add a gallery example for the frames that depend on Earth's magnetic dipole

[wtbarnes]

In v5.1, three new frames that depend on Earth's magnetic dipole were added: https://docs.sunpy.org/en/stable/whatsnew/5.1.html#coordinate-frames-related-to-the-earth-s-magnetic-dipole. However, we don't have an example that shows how to actually do anything with these frames. We should add a gallery example (or maybe even a how-to guide?) that gives an example of how to create a frame and then create a coordinate in that existing frame.

[Jett-Code]

A galley example should include coordinates plotted by these new frames, that's it?

[nabobalis]

I think we need to work out exactly what we want the example to do, @ayshih do you have some suggestions?

[IcyArse]

If I am correct we should just include code snippets demonstrating each coordinate frame and 'how to use them' example, considering definitions for all the parameters is already present in the documentation we shouldn't need explanation for them. Giving us clear and concise code examples.

[nabobalis]

If I am correct we should just include code snippets demonstrating each coordinate frame and 'how to use them' example, considering definitions for all the parameters is already present in the documentation we shouldn't need explanation for them. Giving us clear and concise code examples.

The idea behind an example is to try and explain and provide context to what is going on and why values might be chosen for example. It is more than just a few code blocks.