Code refactoring to get translated utilities at the same place

[noliveleger]

Checklist

1. If you've added code that should be tested, add tests
2. If you've changed APIs, update (or create!) the documentation
3. Ensure the tests pass
4. Make sure that your code lints and that you've followed our coding style
5. Write a description of your work suitable for publishing on our forum
6. Mention any related issues in this repository (as #ISSUE) and in other repositories (as kobotoolbox/other#ISSUE)
7. Open an issue in the docs if there are UI/UX changes

Additional info

full_name property is back to name to avoid big migrations in existing environments.
And it is not possible to hide this field (even if it is still possible to toggle its required flag)

[LMNTL]

I tried to break it, seems solid. Didn't know you could use newlines in constance field descriptions, that's useful!

[noliveleger]

I tried to break it, seems solid. Didn't know you could use newlines in constance field descriptions, that's useful!

I created a proof-of-concept with markdown support. I would need to create propose a PR on Constance repo. Maybe one day.