allow date comparisons in segment rules

[orionxiao]

Is your feature request related to a problem? Please describe.

I would like to be able to do date comparisons on a trait in a way that is easy for non-technical users to configure.

Describe the solution you'd like.

New rule operators that allow for date comparison, e.g. some_trait [before | on | after] YYYY-MM-DD, where some_trait could be an ISO-formatted date string, epoch time, or some other format (doesn't really matter). In terms of impl, would probably just be a wrapper around numeric comparison with epoch time.

Describe alternatives you've considered

This is currently possible with numeric comparison if we use epoch time on both sides. However, it would be a nice QOL feature (especially for non-technical users) if we didn't have to do the conversion or think about epoch time at all.

Additional context

No response