## Is your feature request related to a problem?
See [this](https://github.com/PostHog/posthog/pull/9139/files/2754c0fd6633c806def5c328d491421ae7de0c19#diff-7f0217a57a02b6ebd709f6aa7bf43760b2d5a53069aee2b7fea27fdad1caadf1) for more info.


## Describe the solution you'd like

> This is used by django-rest-hooks, the library we use to integrate with Zapier. Specifically, this fires our Zapier integration's Triggers. However, the only trigger that actually matters is the "action_performed" one, and that has been completely delegated to the plugin server for a while. We can remove this Python cruft then, along with django-rest-hooks, but first we need to make sure action_defined and annotation_created actually are unused, and roll out an update to https://github.com/PostHog/posthog-zapier that'd remove those two completely.


## Describe alternatives you've considered

Do nothing
posthog/settings/web.py
"posthog.middleware.CsvNeverCacheMiddleware",
    "whitenoise.middleware.WhiteNoiseMiddleware",
    "axes.middleware.AxesMiddleware",
    "posthog.middleware.AutoProjectMiddleware",
    "posthog.middleware.CHQueries",
    "django_prometheus.middleware.PrometheusAfterMiddleware",
]
if STATSD_HOST is not None:
    MIDDLEWARE.insert(0, "django_statsd.middleware.StatsdMiddleware")
    MIDDLEWARE.append("django_statsd.middleware.StatsdMiddlewareTimer")
try:
    from ee.apps import EnterpriseConfig  
except ImportError:
    pass
else:
    INSTALLED_APPS.append("rest_hooks")
    INSTALLED_APPS.append("ee.apps.EnterpriseConfig")
try:
    import django_extensions  
except ImportError:
    pass
else:
    INSTALLED_APPS.append("django_extensions")
DATA_UPLOAD_MAX_MEMORY_SIZE = 20971520  
ROOT_URLCONF = "posthog.urls"
TEMPLATES = [
    {
        "BACKEND": "django.template.backends.django.DjangoTemplates",
        "DIRS": ["frontend/dist", "posthog/templates", "posthog/year_in_posthog"],
        "APP_DIRS": True,