GitLab

* Updates Portuguese documentation for Diffusers library

Enhances the Portuguese documentation with:
- Restructured table of contents for improved navigation
- Added placeholder page for in-translation content
- Refined language and improved readability in existing pages
- Introduced a new page on basic Stable Diffusion performance guidance

Improves overall documentation structure and user experience for Portuguese-speaking users

* Removes untranslated sections from Portuguese documentation

Cleans up the Portuguese documentation table of contents by removing placeholder sections marked as "Em tradução" (In translation)

Removes the in_translation.md file and associated table of contents entries for sections that are not yet translated, improving documentation clarity