User Interface for Granular Control of Jetpack Sitemaps

We received the following suggestion [from a user in the forums](https://wordpress.org/support/topic/stop-jetpack-from-including-pages-marked-as-noindex/#post-10492008):

> Dynamic sitemap creation is a great feature, except it makes it easy to inadvertently show everything to every search engine.
>
> Seems the Jetpack plugin would benefit from offering easy control of such functionality through the UI.
>
> Pretty sure there are a lot of people that see ‘automatic sitemap’ and think ‘cool’, without realizing they are inadvertently announcing every page / post on their site to every search engine, even development pages with development titles.

> It makes perfect sense for Jetpack to obey the ‘noindex’ settings. Jetpack ought to allow users to create a ‘don’t show list’ or a don’t show flag. Otherwise, ‘noise’ from pages and posts that aren’t relevant sitemap overwhelms the Given the custom tweaking necessary to disable that

No files, tests, or entry points are identified. Start by locating Jetpack's existing sitemap implementation and settings UI, then determine how noindex settings and exclusions are currently handled. Done should include an understandable UI for granular sitemap control and behavior that reflects those choices.

Written by the indexing model from the issue text.