Rings should be configurable per service

[bnookala]

As a:

SPK user

I want:

Rings to be configured on a per-service basis

So that:

I can disable rings altogether for a single service, or add more rings to any one service

Describe the solution you'd like:

• Creating a service should allow me to specify the rings I want configured for that service (possibly with a default set of rings if I do not provide any rings)
• HLD lifecycle pipeline can then set up rings on a per-service basis

Acceptance Criteria:

• [ ] spk create service should allow me to specify rings I want configured
• [ ] Lifecycle pipeline should only create the rings that are configured on a service

Describe alternatives you've considered:

Keeping the status quo and using only the set of rings that are configured on a project

Additional context:

I may possibly have a service that I build in my application repository that only needs a single ring - with our current approach to rings, we would be building multiple rings for this service.

Does this require updates to documentation?:

Yes