(captiveportal, new) add certificate field to form

src/opnsense/mvc/app/controllers/OPNsense/CaptivePortal/forms/dialogZone.xml

@@ -41,6 +41,13 @@
         <help><![CDATA[Clients will be disconnected after this amount of time, regardless of activity. They may log in again immediately, though. Leave this field blank for no hard timeout (not recommended unless an idle timeout is set).]]></help>
         <hint>Type or select server.</hint>
     </field>
+    <field>
+        <id>zone.certificate</id>
+        <label>SSL certificate to use</label>
+        <type>dropdown</type>
+        <help><![CDATA[If provided, all traffic will be transmitted over an HTTPS connection to protect against eavesdroppers.]]></help>
+        <hint>Type or select server.</hint>
+    </field>
     <field>
         <id>zone.description</id>
         <label>description</label>