add ticket purchase page

Co-authored-by: Jan-Marlon Leibl <jleibl@proton.me>
Reviewed-on: http://git.simonis.lol/projects/abiball/pulls/13
Reviewed-by: jank1619 <jan@kjan.email>

config/packages/doctrine_migrations.yaml

@@ -0,0 +1,6 @@
+doctrine_migrations:
+    migrations_paths:
+        # namespace is arbitrary but should be different from App\Migrations
+        # as migrations classes should NOT be autoloaded
+        'DoctrineMigrations': '%kernel.project_dir%/migrations'
+    enable_profiler: false