Fix bug DNN-3133: update the codebase with code review result:
	1. change sp parameter pageSize into numberOfUsers;
	2. remove AuthorUserId in index;
	3. remove empty row in index;
	4. make first name be add in every index;
	5. in search result page, change user to Users;
	6. avoid duplicate results in result page.
Fix bug DNN-3133: missed 2 files in last commit.