documentation

Pull request #780: feature/ZBXNEXT-276-6.4-D2-API (LDAP & SAML user provisioning).

Merge in WEB/documentation from feature/ZBXNEXT-276-6.4-D2-API to release/6.4

* commit 'a39a078ec4b41dc7d054e335bdae9dc1461cbd40':
  [ZBXNEXT-276] LDAP & SAML user provisioning (updated formatting, .create example, `bind_password` param)
  [ZBXNEXT-276] LDAP & SAML user provisioning (updated userdirectory.update/.test example descriptions)
  [ZBXNEXT-276] Updated Userdirectory API parameters end examples
  [ZBXNEXT-276] LDAP & SAML user provisioning (updated authentication.get param "ldap_userdirectoryid")
  [ZBXNEXT-276] LDAP & SAML user provisioning (updated Authentication API)