Allow to configure custom domain instead of `consul` and without `.service` suffix.

#### Feature Description

In docker-compose I can refer services like ., but inside hashicorp consul is uses .service.

#### Use Case(s)

It would be nice to be able to create similar domain names without touching containers to refer . instead .service.

The issue does not name any files, tests, or entry points. Start by locating Consul's service-discovery DNS handling and its configuration surface, then determine how a custom domain and removal of the `.service` suffix should interact with existing behavior; done means the requested names work without container changes and are covered by tests.

Written by the indexing model from the issue text.