Implement i18n support

[rypptc]

Fixes

• Related to #99 by @darkshredder

Description

• Added i18n dependencies (Babel, polib, transifex-python) to Pipfile
• Updated i18n settings in settings.py
• Added translation marks in templates, models, views, and tests
• Integrated i18n URL patterns for language support
• Added a language selection dropdown in the header
• Ran makemessages to generate translation files (machine-translated into Spanish for testing) and compiled messages using compilemessages

Technical details

This implementation provides basic Spanish translations for testing. Full integration with Transifex for managing translations will be handled in future steps. The language selection dropdown is implemented using Django’s i18n framework, ensuring smooth language switching without the need for custom JavaScript.

Screenshots

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.
• [x] 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. ```

[rypptc]

All requested changes have been made, I made style checks with isort, black and flake8 as indicated, and legaldb main branch has been merged into the features/implement-internationalization branch, and all existing conflicts were solved.

[rypptc]

Thank you very much, great experience!!

[TimidRobot]

Deployed to production Fri Nov 1 08:07:52 PDT 2024: https://github.com/creativecommons/legaldb/pull/261#issuecomment-2452055177