DOC: Adds example for using DMSP supporting methods.

[rstoneback]

Description

Addresses #41

Adds examples for multiple DMSP methods. Does not currently have an example for the update ephemeris as we don't currently have a public data source for that data.

Type of change

Please delete options that are not relevant.

• Documentation Update

How Has This Been Tested?

No code changes. Visual inspection of output documentation.

Test Configuration

• Operating system: MacOS
• Version number: Python 3.8

Checklist:

• [x] Make sure you are merging into the develop (not main) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have linted the files updated in this pull request
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to CHANGELOG.md, summarizing the changes

If this is a release PR, replace the first item of the above checklist with the release checklist on the pysat wiki: https://github.com/pysat/pysat/wiki/Checklist-for-Release

[rstoneback]

I added this example to pysatTutorials as well under 'why not?'. I have an additional hemisphere selection function there that I can bring over here, if desired.

[rstoneback]

Thanks @aburrell! I misread one of your comments at first. The upside of that is I added metadata to the DMSP methods. I also added the portion requested once I sorted things out. I'll leave future reviews on this to @JonathonMSmith per previous request.

[rstoneback]

I followed the example and found some things that need to be fixed. More importantly, my figure does not match the example figure.

I have updated my figure to the correct one. Previous figure had a hemisphere filter on there.

[rstoneback]

Looks much better! Since I requested changes on this one, I am willing to see it through. I'll just need @JonathonMSmith to take over for me on the tutorials. 🐴

Sounds good. Label updated to read '2D Horizontal Ion Drift'. Could be changed to '2D Roughly Horizontal ...' 🐒

[rstoneback]

muchas gracias!