Zabbix

.......PS. [ZBXNEXT-5626] added database character set check

* commit '1073d6afc73538d846c5e55c9f9d77044a9013a8':
  .......... [ZBXNEXT-5626] added ChangeLog entry
  .......PS. [ZBXNEXT-5626] fixed code style
  .......PS. [ZBXNEXT-5626] set utf8 as only supported character set for Oracle database
  .......PS. [ZBXNEXT-5626] fixed code style
  .......PS. [ZBXNEXT-5626] changed error message
  .......PS. [ZBXNEXT-5626] removed unused variable
  .......PS. [ZBXNEXT-5626] added three Unicode character sets as supported for Oracle database
  .......PS. [ZBXNEXT-5626] amended warnings
  .......PS. [ZBXNEXT-5626] log warning if cannot check character set
  .......PS. [ZBXNEXT-5626] added database character set checking on proxy
  .......PS. [ZBXNEXT-5626] checked return from database as string, not converting to int
  .......PS. [ZBXNEXT-5626] checked database character set

(cherry picked from commit 32a1e56bd2132ae81cbc51aa5e556403c93fe053)
(cherry picked from commit 7a62e6d0e409da92a438d1e02a4f8c0264b6672e)