Recipes Block: Primary issue

This issue lists the remaining items to address before the recipe block introduced in #24343 can be launched.

- [ ] Transform the recipe shortcode into the recipe block.
- [ ] Ensure strings in templates can be translated.
- [ ] Handle focus better when entering ingredients or directions #24904
> When adding ingredients, ideally when hitting enter after adding my first ingredient, I'd like a second ingredient to be automatically created, and the focus be moved there so I can keep adding ingredients, one at a time, without having to rely on my mouse, just like I would if I were using a list block.
- [ ] Add formatting options (italic, bold, ...) to the ingredient list if possible.
- [ ] Add icons for block and inner blocks. #24904
- [ ] Add keywords for better block discoverability. #24904
- [ ] Add tests for the block. See other blocks (e.g. Subscriptions) for some examples.

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Internal references:

- pdF78r-hm-p2
- pdqkMK-fe-p2

Previous references:

- https://github.com/Automattic/jetpack/pull/10270
- https://github.com/Automattic/wp-calypso/pull/27665