Push resource sorting logic to the repository layer

[danail-branekov]

Background

The handler layer is supposed to deal with request/protocol details only and delegate all logic to the repository layer. Hoewver there are a couple of places where soring resources takes place in the handler:

• api/handlers/app.go
• api/handlers/service_instance.go
• api/handlers/role.go
• api/handlers/buildpack.go
• api/handlers/package.go

Action to take

Push sorting logic down to repo layer. We can take inspiration from the deployment repo where it has already been solved