add allow_invalid_cert field to application model and update related forms and config processing

app_gateway/migrations/0007_application_allow_invalid_cert.py

@@ -0,0 +1,16 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('app_gateway', '0006_alter_accesspolicy_policy_type'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='application',
+            name='allow_invalid_cert',
+            field=models.BooleanField(default=False, help_text='Allow invalid or self-signed TLS certificates from the upstream'),
+        ),
+    ]