sql: Generalize date/time parsing

Jesse Seldess (jseldess) commented:


PR: https://github.com/cockroachdb/cockroach/pull/31758

From release notes:
> CockroachDB now accepts a wider variety of date, time, and timestamp formats. [#31758][#31758] {% comment %}doc{% endcomment %}

Jira Issue: DOC-205