This widget adds a button
add_google_style_button(my_html, into = "", material_id, ...)html in a vector of strings; output from 'create_html'.
character string; unique identifier of a line in the html. Element id is highly recommended.
Material id from google material design, e.g. play_circle_outline. More other options, see https://material.io/icons/.
Other parameters to be passed as tag attributes.