fourth state of Provider

- When a service function is created via RESTconf, internally
  we create SFF and SFP
- When a service function chain is created we patch SFF and SFP
  with the final info to send to devices

Change-Id: I9ef2c82a02ca08e7a58ddce8559da3e58345ee57
Signed-off-by: Reinaldo Penno <rapenno@gmail.com>