Fix/4.0.x/soc 4114

Fix description:
* Add a list to contain users FullNames to ```org.exoplatform.social.service.rest.PeopleRestService.UserNameList```.
* Return a list of ```fullNames``` along with ```names``` when calling _/social/people/suggest.{format}_ with query parameter _&typeOfRelation=user_to_invite_.
* Use ```fullNames``` Array Object to build search result list.