[Tock Studio] Faqs : Html wysiwyg editor + I18nLocalizedLabels edition + Footnotes

[rkuffer]

Works with https://github.com/theopenconversationkit/tock/pull/1778

Features :

• Wysiwyg editing of faq answers in html format (markdown to come).
• Faqs now use an I18nLabel as answer. This allows customization of the faq answer for all locales/connectors/interfaceTypes combinations
• Possibility to define footnotes for the faqs answers