## Is your feature request related to a problem?

Currently the funnel time to convert query (added in #4947) only allows measuring time it took to a specific step from the one immediately preceding it. However it'd be useful to also bin by the _total_ time to convert – how long it took to complete the funnel (reach the last step) from entering it (reaching the first step).

## Describe the solution you'd like

Right now `ClickhouseFunnelTimeToConvert` uses only `Filter.funnel_to_step`. It should also be able to work with `Filter.funnel_from_step`. If `funnel_from_step` is `0` and `funnel_to_step` is `len(steps)-1`, that'd be the total time to convert.

#### *Thank you* for your feature request – we love each and every one!

ee/clickhouse/queries/funnels/test/test_funnel_time_to_convert.py
)
        funnel_trends = ClickhouseFunnelTimeToConvert(filter, self.team, ClickhouseFunnel)
        results = funnel_trends.run()
        
        self.assertEqual(
            results,
            [
                (2220.0, 2),  
                (29080.0, 0),  
                (55940.0, 0),  
                (82800.0, 1),  
            ],
        )
    def test_custom_bin_count(self):
        _create_person(distinct_ids=["user a"], team=self.team)
        _create_person(distinct_ids=["user b"], team=self.team)
        _create_person(distinct_ids=["user c"], team=self.team)
        _create_event(event="step one", distinct_id="user a", team=self.team, timestamp="2021-06-08 18:00:00")
        _create_event(event="step two", distinct_id="user a", team=self.team, timestamp="2021-06-08 19:00:00")
        
        _create_event(event="step three", distinct_id="user a", team=self.team, timestamp="2021-06-08 21:00:00")
        _create_event(event="step one", distinct_id="user b", team=self.team, timestamp="2021-06-09 13:00:00")
        _create_event(event="step two", distinct_id="user b", team=self.team, timestamp="2021-06-09 13:37:00")
        
        _create_event(event="step one", distinct_id="user c", team=self.team, timestamp="2021-06-11 07:00:00")
        _create_event(event="step two", distinct_id="user c", team=self.team, timestamp="2021-06-12 06:00:00")
        
        filter = Filter(
            data={
                "insight": INSIGHT_FUNNELS,