## Is your feature request related to a problem?

As a team accumulates data, they will have events/properties that are no longer in use that clutter their app.

Example from our team:
![image](https://user-images.githubusercontent.com/148820/143202334-42d73ab6-13be-4661-ba7a-83c86788b9e8.png)


## Describe the solution you'd like

Under event/properties stats allow 'hiding' events/properties from view.

## Describe alternatives you've considered

Alternatively, go the route of "verified" events/properties (as He@p) does - show those first. See also https://help.heap.io/category/heap-administration/data-governance/

## Additional context

Note: Existing reports, etc should still work well even with 'removed' events/properties.

Related: https://github.com/PostHog/posthog/issues/7126

#### *Thank you* for your feature request – we love each and every one!

posthog/api/test/test_event_definition.py
action = Action.objects.create(team=self.demo_team, name="action1_app")
        response = self.client.get("/api/projects/@current/event_definitions/?search=app&event_type=event")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 2)
        self.assertNotEqual(response.json()["results"][0]["name"], action.name)
    def test_event_type_event_custom(self):
        response = self.client.get("/api/projects/@current/event_definitions/?event_type=event_custom")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 5)
    def test_event_type_event_posthog(self):
        response = self.client.get("/api/projects/@current/event_definitions/?event_type=event_posthog")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 1)
        self.assertEqual(response.json()["results"][0]["name"], "$pageview")
@dataclasses.dataclass
class EventData:
    """
    Little utility struct for creating test event data
    """
    event: str
    team_id: int
    distinct_id: str
    timestamp: datetime
    properties: Dict[str, Any]
def capture_event(event: EventData):