Enhance SDC capabilities

- How to extend the ability to expose configurable parameters to VID?
- Is there a need to better support TOSCA? E.g. support more TOSCA syntax.
- Is there a need to revise/improve the current csar spec?
- For the Categories in the Service Catalog, can we support update and delete in addition to add?
- How to support PNF modeling and onboarding?
- What kind of VNF and service template test should be implemented in SDC?
- How to design and orchestrate complex services, such nested services (a top-level service comprises multiple sub-services), multi-domain services, and services including both VNFs and PNFs?
- Any plan to create a unified development environment where SDC also integrate workflow design, CLAMP, policy design, and others?