Feature request: Markdown To PDF

We currently have a `Render Markdown` operation, it would be good if we could render the markdown and then save the output as a PDF.

This could be an extension of the `Render Markdown` operation through a checkbox or it could potentially be it's own standalone operation.

There seems to be a good amount of libraries that achieve converting markdown files into PDFs so hopefully this operation will be fairly trivial to implement.

Start by locating the existing Render Markdown operation and trace how its rendered output is handled. Compare the checkbox extension and standalone-operation approaches, then identify a suitable Markdown-to-PDF library; done means Markdown can be rendered and saved as a PDF through a clear, tested user flow.

Written by the indexing model from the issue text.