Directory creation not working properly when set to subpath not owned by `root`

[rasmus-kirk]

systemd-tmpfiles is annoying, need to do some testing/research to figure out what to do. Probably will do nothing, but I'll keep this open if people run into the issue.

I have also updated the documentation describing the issue.

How to fix: Don't set mediaDir and stateDir to home! If in doubt, just don't set them at all, that works perfectly fine.

[rasmus-kirk]

If this is more of a feature than a bug, then I would like nix to at least refuse to build if the subpath is not owned by root, with a nice error message. I have no idea how that could be done though, since building must be "pure".

EDIT: I don't think this is actually possible, so I'll just leave this issue open, if anyone runs into this issue.