Migrate from github to gitea + some improvements

frontend/src/app/Services/profile.service.ts

@@ -3,7 +3,7 @@ import { Injectable } from '@angular/core';
 import { Observable } from 'rxjs';
 import { TokenStorageService } from './token.service';
 
-const API_URL = 'https://gruppe1.testsites.info/api/';
+const API_URL = '/api/';
 
 @Injectable({
   providedIn: 'root',
@@ -77,7 +77,7 @@ export class ProfileService {
    */
   public addCronString(cron: string): Observable<any> {
     return this.http.put(
-      'https://gruppe1.testsites.info/api/user' + '/setCron',
+      '/api/user' + '/setCron',
       {
         cron,
       },