[TIMOB-27813] Convert wiki guide content to Markdown compatible with Docsy

As part of our automated doc publishing process we do an HTML export of the wiki content and eventually get that into JSDuck/Guides content that goes out to docs.appcelerator.com We'd like to publish to the Open Docs project and will need a way to convert the exported wiki contents into docsy-compatible markdown. Ideally e'd run this in an automated way without manual tweaks as for some time we'll have both endpoints/sites as targets (and downstream changes to markdown would get overwritten by the next publish).