18: Adapt according to needs of first actual implementation (CR)

Task-Url: #18

dariahsp-core/src/main/java/eu/dariah/de/dariahsp/web/controller/CommonLoginController.java

@@ -48,10 +48,11 @@ public class CommonLoginController {
 	 * @return login view
 	 */
 	@RequestMapping("/login")
-    public String loginForm(Map<String, Object> map, @RequestParam(value = "url", required = false) String requestUrl) {
+    public String loginForm(Map<String, Object> map, @RequestParam(value = "url", required = false) String requestUrl, @RequestParam(value = "error", required = false) String error) {
         final FormClient formClient = (FormClient) config.getClients().findClient(securityConfig.getLocal().getAuthorizerName()).orElseThrow();    
         map.put("callbackUrl", formClient.getCallbackUrl());
         map.put("requestUrl", requestUrl);
+        map.put("error", error);
         return loginView;
     }