Added translated documents to pt-BR:

- README_PT-BR.md
- CHANGELOG_PT-BR.md
- Como_add_um_novo_tradutor.md
- saladict_pt-br.md
- Manual_TuanziOCR_pt-BR.md

Added a shortcut to `README_PT-BR.md` in the README.md files of other existing languages.

Changed the text in `Tuanzi OCR Instructions (Chinese only)` in `README_EN.md` to the correct path for the Chinese document, and added the information/path for the pt-BR document.