google-compute-config: sync with upstream units

With local-fs.target part of sysinit.target
(https://github.com/NixOS/nixpkgs/pull/61321), we don't need to add it
explicitly to certain units anymore, and can change dependencies like
they are in other distros (I picked from Google's official CentOS 7
image here).

Like them, use StandardOutput=journal+console to pipe google-*.service
output to the serial console as well.