Version dropdown

[altheaden]

This PR switches the documentation workflows for MPAS-Analysis to use sphinx with @xylar's custom version switcher instead of using sphinx-multiversion.

Checklist

• Documentation has been built locally and changes look as expected
• Testing comment in the PR documents testing used to verify the changes

[xylar]

Change this to the new syntax:
https://mpas-dev.github.io/MPAS-Analysis/develop/users_guide/quick_start.html#generating-documentation

Here's the Polaris version:
https://docs.e3sm.org/polaris/main/developers_guide/building_docs.html

[xylar]

I think we're still missing changes from:
https://github.com/E3SM-Project/polaris/pull/308/files

I'm seeing docs/_templates/layout.html that is missing here. Please check if there are any other changes that didn't make the port over.

[xylar]

@altheaden, one more place that needs updating:

MPAS-Analysis/suite/run_suite.bash

Lines 43 to 45 in 909e6c9

	cd docs
	make clean
	make html

[altheaden]

@xylar I think the missing files and other issues you noticed have been fixed now. Can you take another look when you get a chance?

[xylar]

@altheaden, we're almost there! Just a few more small changes are needed. With these, I was able to run the developer test suite and get a version of the documentation with the dropdown:
https://web.lcrc.anl.gov/public/e3sm/diagnostic_output/ac.xylar/analysis_testing/chrysalis/version-dropdown/docs/test/

[altheaden]

@xylar I fixed those issues and located one more place where things needed updating. Does everything look okay to you?

[xylar]

Ah, great! Thanks for finding the tutorial as well!

I was tempted to just merge but I think I should run the test suite with the latest changes to make sure everything works. I'll report back soon.

[xylar]

Yep, looks good!

https://web.lcrc.anl.gov/public/e3sm/diagnostic_output/ac.xylar/analysis_testing/chrysalis/version-dropdown/docs/test/