Add a footer note for authors to add a section in end of page. Adding a font-size piece of code is not user friendly for authors.

I want to be able to select adding footer notes so the authors can select the style without having to add a piece of code. 

Handbook idea:  https://planet4.greenpeace.org/idea/footer-notes/ ‎

TASKS:

• Explore Gutenberg native add-on or plugin to add to paragraph block (where we have subscript?)
• Review plugin
• Asses feasibility