openvpn: missing p2p shared key settings

There may be more, at least I don't see the difference between
TLS and shared key for most settings, except certificate setup.

The client traffic redirect is probably also wrong, but for now
provide consistency with TLS.

PR: https://forum.opnsense.org/index.php?topic=3908.0

src/www/vpn_openvpn_server.php

@@ -1142,7 +1142,7 @@ endif; ?>
                         <input id="serverbridge_dhcp_end" name="serverbridge_dhcp_end" type="text" class="form-control unknown" size="20" value="<?=$pconfig['serverbridge_dhcp_end'];?>" />
                       </td>
                     </tr>
-                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user">
+                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_p2p_shared_key opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user">
                       <td width="22%" ><a id="help_for_gwredir" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Redirect Gateway"); ?></td>
                       <td>
                         <input name="gwredir" id="gwredir" type="checkbox" value="yes" <?=!empty($pconfig['gwredir']) ? "checked=\"checked\"" : "" ;?> />
@@ -1153,7 +1153,7 @@ endif; ?>
                         </div>
                       </td>
                     </tr>
-                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user opt_gwredir">
+                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_p2p_shared_key opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user opt_gwredir">
                       <td width="22%" ><a id="help_local_network" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("IPv4 Local Network"); ?></td>
                       <td>
                         <input name="local_network" type="text" class="form-control unknown" size="40" value="<?=$pconfig['local_network'];?>" />
@@ -1167,7 +1167,7 @@ endif; ?>
                         </div>
                       </td>
                     </tr>
-                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user opt_gwredir">
+                    <tr class="opt_mode opt_mode_p2p_tls opt_mode_p2p_shared_key opt_mode_server_tls opt_mode_server_user opt_mode_server_tls_user opt_gwredir">
                       <td width="22%" ><a id="help_for_local_networkv6" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a><?=gettext("IPv6 Local Network"); ?></td>
                       <td>
                         <input name="local_networkv6" type="text" class="form-control unknown" size="40" value="<?=$pconfig['local_networkv6'];?>" />