Trigger daemons from cos-gpu-installer (instead of cos-extensions)

BUG=b/502284908
TEST=Run custom cos-extensions and custom cos-gpu-installer on VMs, installing grid and non-grid GPU drivers. On grid: test license and CUDA workload.
`sudo systemctl list-units --type=path | grep nvidia` and verify the right services are running.
RELEASE_NOTE=None

Change-Id: I6778d527d76b90654b56cc778f76a5401ea165eb
Reviewed-on: https://cos-review.googlesource.com/c/cos/tools/+/149184
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Cloud-Build: 228075978874@cloudbuild.gserviceaccount.com <228075978874@cloudbuild.gserviceaccount.com>
Tested-by: Miri Amarilio <mirilio@google.com>