Add K8S and CF annotations to context object and CF bind resource
Add K8S and CF annotations to context object and CF bind resource

Specify that When present the annotations must be non-empty. The
rationale for this is to:
- optimize the payload by avoiding that platforms send empty
   annotations keys
- simplify service authors work that don't need to handle inconsistent
  platform behaviors

The specs however let platform choose the criteria for sending
annotations (e.g. sensible defaults or user opt-in), and therefore
annotations keys are still optional.

servicebroker/servicebroker,openservicebrokerapi/servicebroker,servicebroker/servicebroker,servicebroker/servicebroker