Support posting articles to Write.as / WriteFreely with [Micropub](https://indieweb.org/micropub).
## Intended Outcome
With support for Micropub, users can publish to WriteFreely with popular apps like iA Writer.
## How will it work?
Users will be able to authenticate with WriteFreely in apps that support Micropub, and publish posts.
Beyond that, they'll be able to include photos via Snap.as integration (TODO: create task).