Generic solver interface

[evaleev]

• reorg scalapack code
• add lapack solvers for
  • DistArray (collective)
    • cholesky
      • cholesky
      • cholesky_inv
      • cholesky_solve
      • cholesky_lsolve
    • heig
      • std
      • generalized
    • lu
    • svd
  • contiguous tensors (non-collective)
    • cholesky
      • cholesky
      • cholesky_inv
      • cholesky_solve
      • cholesky_lsolve
    • heig
    • lu
    • svd

[evaleev]

@wavefunction91 FYI I started on the generic interface. Unfortunately probably need to reorder arguments in scalapack solver API to bring all non-scalapack-specific args forward. This will probably break some NWX code

[evaleev]

@asadchev F* API signatures differ between MADNESS and the rest of the world, so need smth like:

#ifndef  MADNESS_LINALG_USE_LAPACKE
  TA_LAPACK_CALL(
    gesvd,
    &jobu, &jobvt, &m, &n, a, &lda, s, u, &ldu, vt, &ldvt, &lwork_dummy, &lwork, &info,
    sizeof(char), sizeof(char)
  );
#else
  TA_LAPACK_CALL(
      gesvd,
      &jobu, &jobvt, &m, &n, a, &lda, s, u, &ldu, vt, &ldvt, &lwork_dummy, &lwork, &info
  );
#endif

or do metaprogramming magic dropping by-value args