📝 Add documentation for non-translated pages and scripts to verify them

I realized that, for some pages, the benefit of having some translations is less beneficial than having only the original in English, because the original can change frequently, or the content is mainly injected data from external files. In those cases, the actual content translated is small, but the structure and how the data is injected can get obsolete quickly.

Also in the reference, most of the content is injected from the FastAPI source files, so, the translations are only for a small introduction at the top, but the rest of the content stays in English. And if there were new sections in the reference, those would not be visible in the translations, although the content is almost the same, all in English.

This also means that if the sections of injected data change, those translations become obsolete.

There are also sections that are mainly relevant for the internal team, or about how the project is managed, and having the most recent and precise information is more important than having it in multiple languages (that could get behind).