* maintain only one version
* ceph-client: init
* include ceph-volume python tool in output
nixos/ceph: extraConfig, fix test, wait for ceph-mgr to become active
* run ceph with disk group permission
* add extraConfig option for the global section
needed per cluster
* clear up how ceph.conf is generated
* fix ceph testcase
Since https://github.com/NixOS/nixpkgs/pull/61321, local-fs.target is
part of sysinit.target again, meaning units without
DefaultDependencies=no will automatically depend on it, and the manual
set dependencies can be dropped.
All 5 daemon types can be enabled and configured through the module and the module both creates the ceph.conf required but also creates and enables specific services for each daemon, based on the systemd service files that upstream provides.