Add guidance for when/how Azure services should allow caching of responses

[mikekistler]

Some references:

• https://apisyouwonthate.com/blog/caching-is-hard-draw-me-a-picture/
• https://www.rfc-editor.org/rfc/rfc9111#section-3

One of the guidelines we may want to establish:

⛔ DO NOT include a cache-control: public header in the response to an authorized request.