[WIP] Fix interactive email

Created by: Tirokk

Authored by alina-beck Sep 23, 2019 Closed Oct 2, 2019

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🍰 Pullrequest

• hides toggle button in outlook
• hides toggle button when radio input is not supported
• displays emails in both languages when toggle button is not supported
• displays fallback message: "English version below"

Issues

• fixes #1656 (closed)

Todo

• Test in Outlook on Windows
• Test in Webmail clients – @datenbrei maybe you could help with this?