Setup styles for HTML tags generated by Markdown

[#45242047]
Add a new interactive presenting Markdown support

[#45242047]
Remove 'style' property from text component

[#45242047]

Markdown syntax can be used instead.
Update interactives to use Markdown instead of old 'header' style

[#45242047]
Adjust Markdown header styles to fit interactives well

[#45242047]