## 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
response = self.client.get("/api/projects/@current/event_definitions/?search=app")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 2)  
        
        response = self.client.get("/api/projects/@current/event_definitions/?search=App")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 2)  
        
        response = self.client.get("/api/projects/@current/event_definitions/?search=free tri")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 1)
        for item in response.json()["results"]:
            self.assertIn(item["name"], ["entered_free_trial"])
        
        response = self.client.get("/api/projects/@current/event_definitions/?search=free%20tri%20")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 1)
        for item in response.json()["results"]:
            self.assertIn(item["name"], ["entered_free_trial"])
        
        response = self.client.get("/api/projects/@current/event_definitions/?search=ed mov")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 1)
        for item in response.json()["results"]:
            self.assertIn(item["name"], ["watched_movie"])
    def test_event_type_event(self):