i18n: adds Occitan language

What does this PR change? What problem does it solve?

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PR Checklist

[ ] This change adds/updates translations and I have used the template present here.
[ ] I have enabled maintainer edits for this PR.
[ ] I have verified that the code works as described/as intended.
[ ] This change adds a Social Icon which has a permissive license to use it.
[ ] This change does not include any CDN resources/links.
[ ] This change does not include any unrelated scripts such as bash and python scripts.
[ ] This change updates the overridden internal templates from HUGO's repository.