[Feature Request]: Make RenderableDocument codable #154

Why?

MarkdownView requires markdown parsing when using in a list (using as a single view is fine). Markdown parsing is called every time when the cell/row is reused and it's heavy. This is a perf issue.

Workaround

Current workaround to mitigate is to use a in-memory cache for RenderableDocument.

Suggestions

We can move a step forward and make RenderableDocument conform to Codable protocol. In that way, we can parse ahead and store it wherever we want (e.g. database).