Revert "*: providers and sources -> channels, PolicyModel to PolicyBindingModel that uses custom M2M through"

This reverts commit 7ed3ceb960.

passbook/audit/migrations/0004_auto_20191205_1502.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.2.8 on 2019-12-05 15:02
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("passbook_audit", "0003_auto_20191205_1407"),
+    ]
+
+    operations = [
+        migrations.RemoveField(model_name="event", name="request_ip",),
+        migrations.AddField(
+            model_name="event",
+            name="client_ip",
+            field=models.GenericIPAddressField(null=True),
+        ),
+    ]