In the migration to `tmpfiles.d(5)`, I used the wrong type of file.
Using `f` would write the path to the file as its content, rather than
copy it. Unfortunately `C` and `C+` do not overwrite an existing file,
so using a symlink it the correct solution here.
This means the SSH key file must have `lohr` as an owner... Perhaps I
should make it so the service can read the file itself, rather than
rely on the filesystem location, so that I don't have to contort myself
quite so much to make it work.
Let's consolidate all modules under one path, so that NixOS,
home-manager, and nix-darwin (if I ever end up using it down the line)
would go under the same folder.
Bruno BELANYI