[SciPy-Dev] PROPACK Sparse SVD Integration

Hi all, Matt Haberland and I are happy to open PR gh-14433 <https://github.com/scipy/scipy/pull/14433> to close the long-standing issue gh-857 <https://github.com/scipy/scipy/issues/857> through PROPACK integration into scipy.sparse.linalg.svds based on the previous work done by @jakevdp in pypropack <https://github.com/jakevdp/pypropack/>. This PR includes: - PROPACK wrappers exposing a new 'propack' solver backend for scipy.sparse.linalg.svds - an overhaul and expansion of the scipy.sparse.linalg.svds test suite, documentation, and benchmarks - inclusion of a new PROPACK submodule under the SciPy organization which includes patches for known bugs, Fortran compiler support, and OpenMP issues Thanks, Nicholas