Hypre wrappers

Links to upstream documentation:

• https://hypre.readthedocs.io/en/latest/ch-ij.html
• https://hypre.readthedocs.io/en/latest/ch-solvers.html
• https://hypre.readthedocs.io/_/downloads/en/latest/pdf/
• https://hypre.readthedocs.io/en/latest/api-int-ij.html
• https://hypre.readthedocs.io/en/latest/api-sol-parcsr.html

Checklist:

• HypreVector, HypreParVector
• HypreCSRMatrix
• HypreParCSRMatrix
• implement copy-constructors and copy-assignment operators
• modify our DistributedMatrix to separate the diag and offd blocks like Hypre, so we can bind to its data without actually copying anything

Solvers:

• HypreSolver
• HypreBoomerAMG: refactor/finish setSystemsOptions, setAdvectiveOptions, setElasticityOptions
• interface for configuring solver parameters from command-line
• interoperability between TNL solvers and Hypre preconditioners
• use TNL base classes for Hypre solvers and preconditioners?

General:

• port an example to TNL: https://github.com/hypre-space/hypre/blob/master/src/examples/ex5.c
• GPU support
• make sure Hypre is tested in the CI