get rid of the activity stream middleware

it has bugs and is very confusing

see: https://github.com/ansible/tower/issues/4037

awx/main/tests/functional/api/test_activity_streams.py

@@ -1,7 +1,6 @@
 import pytest
 
 from awx.api.versioning import reverse
-from awx.main.middleware import ActivityStreamMiddleware
 from awx.main.models.activity_stream import ActivityStream
 from awx.main.access import ActivityStreamAccess
 from awx.conf.models import Setting
@@ -61,28 +60,6 @@ def test_ctint_activity_stream(monkeypatch, get, user, settings):
     assert response.data['summary_fields']['setting'][0]['name'] == 'FOO'
 
 
-@pytest.mark.django_db
-def test_middleware_actor_added(monkeypatch, post, get, user, settings):
-    settings.ACTIVITY_STREAM_ENABLED = True
-    u = user('admin-poster', True)
-
-    url = reverse('api:organization_list')
-    response = post(url,
-                    dict(name='test-org', description='test-desc'),
-                    u,
-                    middleware=ActivityStreamMiddleware())
-    assert response.status_code == 201
-
-    org_id = response.data['id']
-    activity_stream = ActivityStream.objects.filter(organization__pk=org_id).first()
-
-    url = reverse('api:activity_stream_detail', kwargs={'pk': activity_stream.pk})
-    response = get(url, u)
-
-    assert response.status_code == 200
-    assert response.data['summary_fields']['actor']['username'] == 'admin-poster'
-
-
 @pytest.mark.django_db
 def test_rbac_stream_resource_roles(activity_stream_entry, organization, org_admin, settings):
     settings.ACTIVITY_STREAM_ENABLED = True