Add initial docs for the DataViews component

[oandregal]

Part of #55083

What?

Add initial docs for the DataViews component and the related APIs: view, fields.

Why?

To communicate and clarify the terminology and APIs in place.

Test

Read document.

[ntsekouras]

Do you think we should also add the type definitions for the interfaces used in the main component or somewhere, now?

[oandregal]

At some point, it'd be good to have them, sure.

Right now, my main concern is to have a high-level map of the code, so to speak. I'd like to give people a little orientation about how to navigate the hundreds of lines of code. Writing things down is how I think, so I am biased towards believing this may be helpful to some others as well.

[github-actions]

Flaky tests detected in b319ef4.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/6558238685
📝 Reported issues:

• [Flaky Test] should insert elements from multiple completers in a single block #47916 in /test/e2e/specs/editor/various/autocomplete-and-mentions.spec.js