## 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/property_definition.py
allow_null=True,
        default=None,
    )
    event_names = serializers.CharField(
        help_text="If sent, response value will have `is_seen_on_filtered_events` populated. JSON-encoded",
        required=False,
    )
    filter_by_event_names = serializers.BooleanField(
        help_text="Whether to return only properties for events in `event_names`",
        required=False,
        allow_null=True,
        default=None,
    )
    excluded_properties = serializers.CharField(
        help_text="JSON-encoded list of excluded properties",
        required=False,
    )
    def validate(self, attrs):
        type_ = attrs.get("type", "event")
        if type_ == "group" and attrs.get("group_type_index") is None:
            raise ValidationError("`group_type_index` must be set for `group` type")
        if type_ != "group" and attrs.get("group_type_index") is not None:
            raise ValidationError("`group_type_index` can only set for `group` type")
        if attrs.get("group_type_index") and not (0 <= attrs.get("group_type_index") < GROUP_TYPES_LIMIT):
            raise ValidationError("Invalid value for `group_type_index`")
        if type_ != "event" and attrs.get("event_names"):
            raise ValidationError("`event_names` can only be set for `event` type")
        return super().validate(attrs)
@dataclasses.dataclass
class QueryContext: