Code review comment for charm-telegraf:bug/1896467

Usually, files in /etc are written with root as owner and possibly a group with group readable permission.

I think something like

host.write_file(
            config_path,
            f.getvalue().encode("UTF-8"),
            owner=root,
            group=TELEGRAF_USER,
            perms=0o640,
)

is more on par with what we expect in /etc.
(0o440 is a possibility if we really want to discourage people to edit the files)

However, I may miss something.
Not a hard block, just something I'm curious about.