Zabbix

A.F....... [ZBX-3783] added validation for user.create(), user.update() and user.delete() methods

 - user.create() and user.update() methods are completely rewritten
 - partially rewritten user.delete() method
 - audit related to user are moved to API side (except unblock functionality)
 - user.updateprofile(), user.addmedia(), user.updatemedia() and user.deletemedia() methods are deprecated
 - added support of "user_medias" options by user.update() method
 - added support of API_TIME_PERIOD data type by API imput validator