add capability for alias links

Signed-off-by: jkoberg <jkoberg@owncloud.com>

changelog/unreleased/add-aliaslink-capability.md

@@ -0,0 +1,7 @@
+Enhancement: Add capability for alias links
+
+For better UX clients need a way to discover if alias links
+are supported by the server. We added a capability under "files_sharing/public/alias"
+
+https://github.com/owncloud/ocis/issues/3983
+https://github.com/owncloud/ocis/pull/3991

services/frontend/pkg/revaconfig/config.go

@@ -167,6 +167,7 @@ func FrontendConfigFromStruct(cfg *config.Config) map[string]interface{} {
 								"default_permissions":               22,
 								"search_min_length":                 3,
 								"public": map[string]interface{}{
+									"alias":                      true,
 									"enabled":                    true,
 									"send_mail":                  true,
 									"defaultPublicLinkShareName": "Public link",