Clean up languages, unused terms detector script, split multiline terms

• Script to search unused translations
• Clean up unused terms in the app (en.json)
• Split multiline terms and upload to poeditor
• Split the translation in all the languages
• Implement a pre-commit hook to avoid new lines characters on en.json
• Add newline removal to language file downloaded
• Add terms update and delete to CI

closes #1604 (closed)
closes #1615 (closed)
closes #1614 (closed)
closes #1611 (closed)
closes #1609 (closed)
closes #1290 (closed) (Poeditor)