## 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
"django.contrib.staticfiles",
    "posthog.apps.PostHogConfig",
    "rest_framework",
    "loginas",
    "corsheaders",
    "social_django",
    "django_filters",
    "axes",
    "drf_spectacular",
]
MIDDLEWARE = [
    "django_prometheus.middleware.PrometheusBeforeMiddleware",
    "posthog.gzip_middleware.ScopedGZipMiddleware",
    "django_structlog.middlewares.RequestMiddleware",
    "django_structlog.middlewares.CeleryMiddleware",
    "django.middleware.security.SecurityMiddleware",
    
    
    
    "posthog.health.healthcheck_middleware",
    "posthog.middleware.ShortCircuitMiddleware",
    "posthog.middleware.AllowIPMiddleware",
    "google.cloud.sqlcommenter.django.middleware.SqlCommenter",
    "django.contrib.sessions.middleware.SessionMiddleware",
    "corsheaders.middleware.CorsMiddleware",
    "django.middleware.common.CommonMiddleware",
    "posthog.middleware.CsrfOrKeyViewMiddleware",
    "django.contrib.auth.middleware.AuthenticationMiddleware",
    "django.contrib.messages.middleware.MessageMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",