Fix serviceusage links, clean up service resource stub

[rileykarson]

Share a more relevant link for consumer quota overrides, and don't link consumer overrides for admin overrides. Note that we didn't ever release the admin resource, so that part's really a noop.

Also remove the yaml for Service. https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/google_project_service is an extremely customized handwritten resource, so that's never going to get used by Terraform.

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[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

Terraform GA: Diff ( 1 file changed, 1 insertion(+), 1 deletion(-))
Terraform Beta: Diff ( 1 file changed, 1 insertion(+), 1 deletion(-))
TF Validator: Diff ( 2 files changed, 3 insertions(+), 3 deletions(-))