[Discovery] Support Spark SQL "VERSION AS OF ..." / "TIMESTAMP AS OF" in tables

[arielshaqed]

Spark SQL added support for VERSION AS OF 1 / TIMESTAMP AS OF '2023-08-01 13:42 sometime around 3.3. Delta Lake is listed as the use-case for this, but a comment there claims Iceberg also works.

Can we support this syntax? Can we use it to support more general ref expressions?

[arielshaqed]

@ozkatz FYI

[github-actions[bot]]

This issue is now marked as stale after 90 days of inactivity, and will be closed soon. To keep it, mark it with the "no stale" label.