Introduce <ListIterator>

[djhi]

Problem

Rendering a custom list is cumbersome. One has to create an iterator component that reads the list context.

The <SingleFieldList> is a good tradeoff, as one can just use a component that reads a RecordContext and it will be displayed several times.

But it’s tied to MUI, so we can’t use it in other UI kits.

Solution

Add a <ListIterator> component, that simply iterates over data, creates a RecordContext, and renders its child n times. It shouldn’t render any wrapper, to let users choose the wrapper of their choice (e.g. <ul>)

It should render either children or a render prop

TODO

• Implementation
• Tests & Stories
• Update <SingleFieldList> and <SimpleList>
• Documentation

How To Test

• https://react-admin-storybook-git-list-iterator-marmelab.vercel.app/?path=/story/ra-core-controller-list-listiterator--using-render
• https://react-admin-storybook-git-list-iterator-marmelab.vercel.app/?path=/story/ra-core-controller-list-listiterator--using-children
• unit tests

Additional Checks

• The PR targets master for a bugfix or a documentation fix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The PR includes one or several stories (if not possible, describe why)
• The documentation is up to date

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