Importer is no compatible with Rusty-Hektor 1.0.0

Also removed a bunch of unnecessary code and extracted the test runner into https://gitlab.gwdg.de/grady-corp/grady-test-runner

core/migrations/0013_auto_20190308_1448.py

+# Generated by Django 2.1.4 on 2019-03-08 14:48
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0012_auto_20190306_1611'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='feedback',
+            name='score',
+            field=models.DecimalField(decimal_places=2, default=0, max_digits=5),
+        ),
+    ]