Add CC 4.0 `et` Estonian (eesti) translations

Known issues

NoDerivitives needs to be translated. For example:
- Autorile viitamine-Mitteäriline eesmärk-NODERIVATIVES 4.0 Rahvusvaheline
- Autorile viitamine-NODERIVATIVES 4.0 Rahvusvaheline
~~RDF/XML generation has issues with title (update to creativecommons/cc-legal-tools-app may be necessary)~~
- ✅ Resolved via creativecommons/cc-legal-tools-app/pull/479

Description

Add CC 4.0 et Estonian (eesti) translations

Thank you to the volunteers that made this happen ❤️

Review Guidelines

See Generated Files Review (generated_files_review.md).

Also with this branch checked out, you can review using creativecommons/index-dev-env.

Tests

Dev/Preview deployment links

4.0 License	Legal code URL
CC BY-NC-ND	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by-nc-nd/4.0/legalcode.et
CC BY-NC-SA	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by-nc-sa/4.0/legalcode.et
CC BY-NC	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by-nc/4.0/legalcode.et
CC BY-ND	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by-nd/4.0/legalcode.et
CC BY-SA	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by-sa/4.0/legalcode.et
CC BY	https://deploy-preview-219--cc-legal-tools.netlify.app/licenses/by/4.0/legalcode.et

Checklist

[x] My pull request has a descriptive title (not a vague title like Update index.md).
[x] My pull request targets the default branch of the repository (main or master).
[x] My commit messages follow best practices.
[x] My code follows the established code style of the repository.
[ ] I added or updated tests for the changes I made (if applicable).
[ ] I added or updated documentation (if applicable).
[x] I tried running the project locally and verified that there are no visible errors.

Developer Certificate of Origin

For the purposes of this DCO, "license" is equivalent to "license or public domain dedication," and "open source license" is equivalent to "open content license or public domain dedication."

Developer Certificate of Origin

``` Developer Certificate of Origin Version 1.1 Copyright (C) 2004, 2006 The Linux Foundation and its contributors. 1 Letterman Drive Suite D4700 San Francisco, CA, 94129 Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Developer's Certificate of Origin 1.1 By making a contribution to this project, I certify that: (a) The contribution was created in whole or in part by me and I have the right to submit it under the open source license indicated in the file; or (b) The contribution is based upon previous work that, to the best of my knowledge, is covered under an appropriate open source license and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the same open source license (unless I am permitted to submit under a different license), as indicated in the file; or (c) The contribution was provided directly to me by some other person who certified (a), (b) or (c) and I have not modified it. (d) I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it, including my sign-off) is maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved. ```

Name	Link
Latest commit	834844e74e35817df086d150185b1e7cef2057f5
Latest deploy log	https://app.netlify.com/sites/cc-legal-tools/deploys/66f175ffdea5820008810add
Deploy Preview	https://deploy-preview-219--cc-legal-tools.netlify.app
Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

creativecommons / cc-legal-tools-data