feat #29: add initial support for mtbfile api tokens

src/main/resources/templates/login.html

@@ -15,7 +15,7 @@
             <form method="post" th:action="@{/login}">
                 <input type="text" id="username" name="username" class="form-control" placeholder="Username" required="" autofocus="">
                 <input type="password" id="password" name="password" class="form-control" placeholder="Password" required="">
-                <button class="" type="submit">Anmelden</button>
+                <button type="submit">Anmelden</button>
             </form>
         </div>
     </main>