Improve Documentation about creating a new service

[robert-elles]

Suggestions to improve the creating a new service guide

In the creating a new service guide to publish a new service one is effectively contributing to ferdium. Therefore it would be helpful to at least mention and link to the contributing guide. Also the guide says that one should fork the repo. When forking github ask you to just for the development branch or the full repo. But in your guides there is no mention of what branch to use for forking. It would help the reader of your guide if you directly state e.g just for the development branch and use it also for contributing.