Zabbix

.......... [DEV-2142] refactored libzbxdbhigh by separation to higher and lower parts

Merge in ZBX/zabbix from feature/DEV-2142-6.3-3 to master

* commit 'eaf60de4faffc85e739a2f2a2d63dfca28079990':
  .......... [DEV-2142] moved zbx_db_mock_field functionality to zabbix_server
  .......... [DEV-2142] cleaned includes
  .......... [DEV-2142] update proxy.c file
  .......... [DEV-2142] code review rework
  .......... [DEV-2142] fixed warnings
  .......... [DEV-2142] added some fixes after merge
  .......... [DEV-2142] moved check_access_passive_proxy() up due to tls dependency
  .......... [DEV-2142] removed commented code
  .......... [DEV-2142] removed redundant include
  .......... [DEV-2142] fixed DBInit
  .......... [DEV-2142] refactored libzbxdbhigh by separation to higher and lower parts