5.0.3: CLI documentation (rebased onto develop) (rebased onto dev_5_0)


This is the same as gh-887 but rebased onto dev_5_0.

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This is the same as gh-868 but rebased onto develop.

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This PR addresses several CLI documentation needs summarized in https://trello.com/c/AmB1db6W/57-5-0-3-documentation-fixes.