Implement sphinx-argparse for conda-build

[travishathaway]

The commands that are documented here:

https://docs.conda.io/projects/conda-build/en/latest/resources/commands/index.html

are out of date with the documentation a user sees when they run conda build --help.

This happens because the command documentation is currently hard-coded. In order to fix this, we need to copy the method conda uses and create the documentation dynamically using the sphinx-argparse plugin.

This issue relates to the following issue:

• Documentation: conda index --no-remove in docs, not in program #4441

[github-actions]

Hi there, thank you for your contribution!

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Thanks!

[jezdez]

Still a thing

[PatSunter]

Is this issue now deprecated by #5235 ?

I.E. if Conda has split out conda-index into a separate project and tool that has to be invoked differently anyway now?