## 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/utils.py
def __init__(self, klass):
        self.klass = klass
        self.instance = None
    def __call__(self, *args, **kwds):
        if self.instance == None:
            self.instance = self.klass(*args, **kwds)
        return self.instance
def get_machine_id() -> str:
    """A MAC address-dependent ID. Useful for PostHog instance analytics."""
    
    
    return hashlib.md5(uuid.getnode().to_bytes(6, "little")).hexdigest()
def get_table_size(table_name):