## 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
ee/settings.py
"""
Django settings for PostHog Enterprise Edition.
"""
import os
from typing import Dict, List
from posthog.settings import AUTHENTICATION_BACKENDS, DEMO, SITE_URL, get_from_env
HOOK_EVENTS: Dict[str, str] = {
    
    "action_performed": "posthog.Action.performed",
}
HOOK_FINDER = "ee.models.hook.find_and_fire_hook"
HOOK_DELIVERER = "ee.models.hook.deliver_hook_wrapper"
AUTHENTICATION_BACKENDS = AUTHENTICATION_BACKENDS + [
    "ee.api.authentication.MultitenantSAMLAuth",
    "social_core.backends.google.GoogleOAuth2",