Update and refine documentation about ARS design and usage

[RichardBruskiewich]

https://github.com/NCATSTranslator/translator-developer-documentation/blob/main/docs/architecture/ars.md

See also https://github.com/NCATSTranslator/TranslatorTechnicalDocumentation/blob/master/docs/architecture/ars_usage.md

(maybe the two pages can be merged?)

Related issue #56 relating to ARS usage notes at https://docs.google.com/document/d/1_a4gE_lY-2oZTrdFMtaZ_pxqNgd-x_1ZYI7hRGfFjng/edit

[tursynay]

@MarkDWilliams , hello. We wanted to follow up about this issue and ask if you could work on this in the next couple of weeks. We hope to wrap some things up before the sept relay. Please let us know if you have any questions about this ask.

[RichardBruskiewich]

Hi @MarkDWilliams, with the Relay behind us, I'm wondering if you might have a few minutes this coming week to rough out some content for the ARS section of the document?