Zabbix

A.F....PS. [ZBXNEXT-5223] added web scenario and HTTP agent with Kerberos authentication delegation

* commit '36aec4f2056f4fff870adaf82367b310d640c219':
  .D........ [ZBXNEXT-5223] fixed ChangeLog
  .......... [ZBXNEXT-5223] added Kerberos checks to selenium tests
  ..F....... [ZBXNEXT-5223] fixed form field validation in web scenarios
  ..F....... [ZBXNEXT-5223] added frontend change for Discovery rules and Item prototypes with Kerberos Authentication
  A.F....... [ZBXNEXT-5223] added frontend change for HTTP agent with Kerberos Authentication
  A.F....... [ZBXNEXT-5223] added frontend change for Web Scenario with Kerberos Authentication
  .......PS. [ZBXNEXT-1856] improved error message in case of older cURL library
  .......PS. [ZBXNEXT-1856] patch for CURLAUTH_NEGOTIATE applied