## 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
"labels": [
                            "Sun. 1 November, 10:20",
                            "Sun. 1 November, 10:21",
                            "Sun. 1 November, 10:22",
                            "Sun. 1 November, 10:23",
                            "Sun. 1 November, 10:24",
                            "Sun. 1 November, 10:25",
                            "Sun. 1 November, 10:26",
                            "Sun. 1 November, 10:27",
                            "Sun. 1 November, 10:28",
                            "Sun. 1 November, 10:29",
                            "Sun. 1 November, 10:30",
                        ],
                        "days": [
                            "2020-11-01 10:20:00",
                            "2020-11-01 10:21:00",
                            "2020-11-01 10:22:00",
                            "2020-11-01 10:23:00",
                            "2020-11-01 10:24:00",
                            "2020-11-01 10:25:00",
                            "2020-11-01 10:26:00",
                            "2020-11-01 10:27:00",
                            "2020-11-01 10:28:00",
                            "2020-11-01 10:29:00",
                            "2020-11-01 10:30:00",
                        ],
                    }
                ],
            )
        def test_hour_interval(self):