API types and client code for the k8s maistra.io group has been moved to the maistra/api project.  We need to now remove this code from maistra/istio and have maistra/istio reference the code in maistra/api.

Work to be done in maistra/istio:

• Add dependency on maistra/api
• Remove pkg/servicemesh/apis and pkg/servicemesh/client
• Update imports

Prerequisite work:

• Verify the types in maistra/api are up to date with the types in maistra/istio