## 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
demo_team: Team = None  
    EXPECTED_EVENT_DEFINITIONS: List[Dict[str, Any]] = [
        {"name": "installed_app", "volume_30_day": 1, "query_usage_30_day": None},
        {"name": "rated_app", "volume_30_day": 2, "query_usage_30_day": None},
        {"name": "purchase", "volume_30_day": 3, "query_usage_30_day": None},
        {"name": "entered_free_trial", "volume_30_day": 7, "query_usage_30_day": None},
        {"name": "watched_movie", "volume_30_day": 8, "query_usage_30_day": None},
        {"name": "$pageview", "volume_30_day": 9, "query_usage_30_day": None},
    ]
    @classmethod
    def setUpTestData(cls):
        cls.organization = create_organization(name="test org")
        cls.demo_team = create_team(organization=cls.organization)
        cls.user = create_user("user", "pass", cls.organization)
        for event_definition in cls.EXPECTED_EVENT_DEFINITIONS:
            create_event_definitions(event_definition, team_id=cls.demo_team.pk)
            for _ in range(event_definition["volume_30_day"]):
                capture_event(
                    event=EventData(
                        event=event_definition["name"],
                        team_id=cls.demo_team.pk,
                        distinct_id="abc",
                        timestamp=datetime(2020, 1, 1),
                        properties={},
                    )
                )
        
        
        calculate_event_property_usage_for_team(cls.demo_team.pk)
    def test_list_event_definitions(self):