## 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/event_definition.py
model = EventDefinition
        fields = (
            "id",
            "name",
            "volume_30_day",
            "query_usage_30_day",
            "created_at",
            "last_seen_at",
            "last_updated_at",
            "tags",
            
            "is_action",
            "action_id",
            "is_calculating",
            "last_calculated_at",
            "created_by",
            "post_to_slack",
        )
    def update(self, event_definition: EventDefinition, validated_data):
        raise EnterpriseFeatureException()
    def get_is_action(self, obj):
        return hasattr(obj, "action_id") and obj.action_id is not None
class EventDefinitionViewSet(