Add WriteFreely

Name: WriteFreely
Homepage: https://writefreely.org/
Example instance: https://paper.wf
Short description: Federated blogging platform
Optional API documentation URL: https://developers.write.as/docs/api/#introduction

Updated this to include more detail

Thanks for doing the research!

Just as with Peertube [1], since WriteFreely is ActivityPub-compatible, I hope we can do something with that.

Because I have tried earlier adding write.as to Keyoxide and that failed [2], the WriteFreely API does not return enough data.