Add staleness clause support to ORDER BY WITH FILL operator

Why it matters

This feature enhances the WITH FILL operator by allowing users to specify the maximum allowed staleness for filled values, improving control over gap-filling behavior in ordered data. It helps maintain data accuracy and performance when filling missing rows in sequences with specified staleness constraints.

How to use it

Users can add the STALENESS clause within the ORDER BY WITH FILL syntax to define the maximum staleness duration for filled values. This is done by appending STALENESS x [UNIT] where x is the staleness limit, allowing fine-grained control of the filling operation.