Better interface for managing the server

[MaelImhof]

Currently the only way to interact with the server is a ribbon button to start it. I want the user to find it clearer whether the server is running and how to interact with the server (stop it, restart it, ...).

• [x] Settings page where the user can see the current status of the server
• [x] Toggle instead of a simple button in the ribbon. Can both start and stop the server, and indicates the state.
• [x] Change icon in the ribbon depending on the current status of the server

[MaelImhof]

I'm satisfied with how it turned out tbh.