## 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_property_definition.py
property = PropertyDefinition.objects.create(
            team=self.team, name="timestamp_property", property_type="DateTime"
        )
        response = self.client.get(f"/api/projects/{self.team.pk}/property_definitions/{property.id}")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        assert response.json()["property_type"] == "DateTime"
    def test_list_property_definitions(self):
        response = self.client.get(f"/api/projects/{self.team.pk}/property_definitions/")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], len(self.EXPECTED_PROPERTY_DEFINITIONS))
        self.assertEqual(len(response.json()["results"]), len(self.EXPECTED_PROPERTY_DEFINITIONS))
        for item in self.EXPECTED_PROPERTY_DEFINITIONS:
            response_item: Dict = next((_i for _i in response.json()["results"] if _i["name"] == item["name"]), {})
            self.assertEqual(response_item["query_usage_30_day"], item["query_usage_30_day"], item)
            self.assertEqual(response_item["is_numerical"], item["is_numerical"])
    def test_list_numerical_property_definitions(self):
        response = self.client.get(f"/api/projects/{self.team.pk}/property_definitions/?is_numerical=true")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.json()["count"], 3)
        self.assertEqual(len(response.json()["results"]), 3)
        properties = sorted([_i["name"] for _i in response.json()["results"]])
        self.assertEqual(properties, ["app_rating", "purchase", "purchase_value"])
    def test_pagination_of_property_definitions(self):