Documentation: Getting Started: How to get additional information about a post with _embed

[krogsgard]

Further explain _embed (or perhaps also move and rephrase current docs). Give example of when this is helpful, like replicating a singular post view. Show example of using embedded data.

[kadamwhite]

@krogsgard Where would you like this to live in the handbook? Is the documentation on linking & embedding sufficient, or should it be expanded?

[kadamwhite]

@krogsgard I'm closing this out, but please re-open if there's specific additions you think we should see