feat(web,server): external domain setting (#6146)

* feat: external domain setting

* chore: open api

* mobile: handle serverconfig-externalDomain

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

server/src/domain/server-info/server-info.service.spec.ts

@@ -184,6 +184,7 @@ describe(ServerInfoService.name, () => {
         loginPageMessage: '',
         oauthButtonText: 'Login with OAuth',
         trashDays: 30,
+        externalDomain: '',
       });
       expect(configMock.load).toHaveBeenCalled();
     });