## Is your feature request related to a problem?

There's only 2 files where we use pandas, but pandas is 49MB and numpy is another 86MB, slowing down builds massively.

## Describe the solution you'd like

Replace pandas with a pure SQL/Python solution in
- posthog/queries/trends.py
- posthog/queries/sessions.py

Both of those have equivalent examples in Clickhouse (ee/clickhouse) that don't use Pandas.

## Describe alternatives you've considered

Continue using Pandas and clogging builds

## Additional context



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

posthog/queries/test/test_trends.py
for i in range(150):
                person_id = "person{}".format(i)
                person_factory(team_id=self.team.pk, distinct_ids=[person_id])
                event_factory(
                    team=self.team, event="$pageview", distinct_id=person_id, timestamp="2020-01-15T12:00:00Z",
                )
            
            result = self.client.get(
                "/api/person/lifecycle",
                data={
                    "date_from": "2020-01-12T00:00:00Z",
                    "date_to": "2020-01-19T00:00:00Z",
                    "events": json.dumps([{"id": "$pageview", "type": "events", "order": 0}]),
                    "shown_as": TRENDS_LIFECYCLE,
                    "lifecycle_type": "new",
                    "target_date": "2020-01-15T00:00:00Z",
                },
            ).json()
            self.assertEqual(len(result["results"][0]["people"]), 100)
            second_result = self.client.get(result["next"]).json()
            self.assertEqual(len(second_result["results"][0]["people"]), 50)
        def test_lifecycle_trend_action(self):