Feature: add interpolation

Hello,

Thanks for making DuckDB so fun to use.

My use case is the analysis of time series for irregularly scattered observations. I would love to see some way for duckdb to provide spatial interpolation methods.

Currently I use python iris interpolate (https://scitools-iris.readthedocs.io/en/stable/userguide/interpolation_and_regridding.html#interpolation). However, this is the slow part compared to other things I can do with DuckDB.

At least having a bilinear interpolation would be nice (preferably on a general quadrilateral. If in regular grid then GSL has code for this). Then maybe integrating libKriging (https://github.com/libKriging/libKriging) though maybe this is too much.

Best,
P.