Change 'pt' to 'pt_PT'

[ignotus666]

Short description of changes This changes 'pt' to 'pt_PT' for the website. Right now on Weblate we have 3 different Portuguese variants (for website + app) when there should be 2, making it consistent for the website and app.

Context: Fixes an issue? Related issues Fixes: #824

Status of this Pull Request Should be ready, it's mostly a renaming of files.

What is missing until this pull request can be merged?

Does this need translation?

No.

Checklist

• [x] I've verified that this Pull Request follows the general code principles
• [x] I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• [x] I'm sure that this Pull Request goes to the correct branch

[ignotus666]

Once this is merged I'll change 'pt' to 'pt_PT' in the docs on Weblate (faster than doing it locally), otherwise the website won't work properly.

[ann0see]

Thanks.