Resolve "Services: listing, add new service, fetch a service in both frontend and the backend."
This MR replaces !29 (closed)
The difference is that this MR divides the feature into commits, one individual change per commit. The fixup commits are reactions to code review comments. MR !29 (closed) has two commits, all changes in these two commits are now divided into many split up commits and fixup commits. Since the changes are identical, all these commits are authored by @godfryd
On top of these commits there are some minor fixup commits to address some more small review comments authored by @matthijs
Closes #24 (closed)