webui: support external flag to trust-add

https://fedorahosted.org/freeipa/ticket/5904

Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>

install/ui/src/freeipa/trust.js

@@ -188,6 +188,12 @@ return {
                 metadata: '@mc-opt:trust_add:bidirectional',
                 widget: 'realm.bidirectional'
             },
+            {
+                $type: 'checkbox',
+                name: 'external',
+                metadata: '@mc-opt:trust_add:external',
+                widget: 'realm.external'
+            },
             {
                 name: 'realm_admin',
                 label: '@i18n:objects.trust.account',
@@ -246,6 +252,11 @@ return {
                         $type: 'checkbox',
                         name: 'bidirectional',
                         tooltip: '@mc-opt:trust_add:bidirectional:doc'
+                    },
+                    {
+                        $type: 'checkbox',
+                        name: 'external',
+                        tooltip: '@mc-opt:trust_add:external:doc'
                     }
                 ]
             },