I now already have nix shells as well as compose.yaml files for
projects. Those were split and are now migrated into a common folder.
That should keep main directory clean and self document that those files
relate to projects, not home manager or systems.
Home-Manager got first level support for calendars and contacts.
Provided integrations are vdirsync and khal which I'm already using.
I therefore migrate from my own setup to the upstream setup.
Issue on home-manager project:
https://github.com/nix-community/home-manager/issues/2335
The composer configuration should also be maintained via home-manager.
The files are added to this repo and added via xdg.
The auth.json is crypted of course as it contains my personal tokens.