## 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_type="String",
            type=PropertyDefinition.Type.GROUP,
            group_type_index=1,
        )
        PropertyDefinition.objects.create(
            team=self.team,
            name="group1 another",
            property_type="String",
            type=PropertyDefinition.Type.GROUP,
            group_type_index=1,
        )
        PropertyDefinition.objects.create(
            team=self.team,
            name="group2 property",
            property_type="String",
            type=PropertyDefinition.Type.GROUP,
            group_type_index=2,
        )
        response = self.client.get(f"/api/projects/{self.team.pk}/property_definitions/?type=group&group_type_index=1")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual([row["name"] for row in response.json()["results"]], ["group1 another", "group1 property"])
        response = self.client.get(f"/api/projects/{self.team.pk}/property_definitions/?type=group&group_type_index=2")
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual([row["name"] for row in response.json()["results"]], ["group2 property"])
        response = self.client.get(
            f"/api/projects/{self.team.pk}/property_definitions/?type=group&search=prop&group_type_index=1"
        )
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual([row["name"] for row in response.json()["results"]], ["group1 property"])
    def test_is_feature_flag_property_filter(self):