feat: add LDAP custom filter support (#1719)

* refactor: improve ldap server code

* feat: custom filter

* fix: fix displayName mapping

* feat: add custom filter search fields

* chore: add license

* chore: i18n

* chore: i18n

* chore: update init field

util/slice.go

@@ -30,3 +30,12 @@ func ContainsString(values []string, val string) bool {
 	sort.Strings(values)
 	return sort.SearchStrings(values, val) != len(values)
 }
+
+func ReturnAnyNotEmpty(strs ...string) string {
+	for _, str := range strs {
+		if str != "" {
+			return str
+		}
+	}
+	return ""
+}