This is a hacky POC showing the use of markdown-it-diagrams for mermaid
and svgbob.  Notable changes:

  * Adds svgbob support for ascii diagrams
  * CDN config isn't tested because svgbob wasm isn't available via CDN
  * Mermaid doesn't show errors.  Error code didn't work before removal.

Signed-off-by: Douglas Mayle <douglas@mayle.org>