Add in Domain id handling into SMS provider BAO

Add in Domain id handling into SMS provider BAO

Add in domain id filtering to delete function

CRM-19961 Treat NULL domain_id values as ok when retriving SMS providers

Ensure domain id only gets set if its not already set

Treat NULL domain_id as valid and also allow for any domain to delete providers that have domain_id which is NULL

Add in API default for domain_id for sms provider

Use value from database if provided even if null otherwise fall back to current domain as default but use the value submitted first

Fix null test on update