feat: htmx powered requests, improved loading indicator

feat: loading indicator and htmx form submit

templates/booking/create_step_2.html.twig

@@ -55,7 +55,7 @@
     <div {{ stimulus_controller('toast') }}></div>
     <h1>Neue Buchung</h1>
     <div class="grid grid-cols-3 gap-8">
-        <div class="col-span-2">
+        <div id="form-wrapper" class="col-span-2">
             <h2>Teilnehmer</h2>
             {{ form_start(form) }}
             {% do form.participants.setRendered %}
@@ -318,7 +318,7 @@
             {% endblock %}
             <div class="flex justify-between">
                 <a href="{{ path('app_booking_create_step_1') }}" class="button bg-button bg-button--secondary">Zurück</a>
-                <button type="submit" class="button bg-button bg-button--secondary">Weiter</button>
+                <button type="submit" class="button bg-button bg-button--secondary" {{ stimulus_action('loading', 'toggle') }}>Weiter</button>
             </div>
             {{ form_rest(form) }}
             {{ form_end(form) }}