Namespace to Gateway - (CLI) Support users creating services and routes without name conflicts

[rustyjux]

As a new API provider following the quick start tutorial, I need to be able to avoid/navigate service name conflicts to get up and running quickly and without issue.

The original idea here was to have a quick-start template prepended namespace to service (argument) to avoid service and route name conflicts (using the client-credientials-shared-idp template).

The new idea is to add an API call (in v3) which checks if a service name (and route?) is available (bcgov/api-services-portal#1065). Once complete, this API call will require implementation within the CLI.