WIP Share paths 2
Attempt at addressing the many, many inconsistencies between the ISO8601 path and the non-ISO8601 path

Can we just get rid of `array_strptime`, and only keep the part that does pattern matching?

@jbrockmendel does the general idea look reasonable? Asking you'd previously commented "yikes" about this 😄 . If so, I'll clean it up and get it ready, just wanted to check that there's not something you know that I don't that would prevent this from being possible
> Asking you'd previously commented "yikes" about this

IIRC the context for that is that `to_datetime` is the last big thing that needs to be updated to support non-nano, and AFAICT that is going to require adding non-trivial complexity to array_to_datetime.  So the prospect of adding more from a different direction merited a "yikes".  But that was and is speculative, so don't let that dissuade you here. doing this the other way round works better, so closing in favour of #50242