> Disclaimer: it's a proof-of-a-concept for an idea discussion.
It's an attempt to introduce a "Render ... Markdown blocks" feature to
the published apps as an option. It shall consider to render markdown
block from the original notebook as an addition to the evaluable cells.
Due to the limited understanding of how app rendering pipeline works,
this commit should be considered only as a proof-of-a-concept, that most
likely will be reworked fully.
P.S. Eventually, it should also take image and section titles cells and
render them.
