ExaSP2 Spackage (#5570)
ExaSP2 Spackage (#5570)

* Added exasp2 spackage

Added spackage for exasp2 proxy app

* Fixed MPI in ExaSP2

Explicitly disabled MPI when not enabled.
Set MPI variant to default as per Spack standards

* Generalized BML Passing for ExaSP2

* Modified to follow spack rules on blas

Fortunately was able to modify exasp2 build system to support spack
model for blas and lapack requirements. No guarantee is made for support
of anything other than originally supported libraries

* Fixed flake8 error

iulian787/spack,tmerrick1/spack,krafczyk/spack,lgarren/spack,skosukhin/spack,mfherbst/spack,EmreAtes/spack,mfherbst/spack,krafczyk/spack,iulian787/spack,lgarren/spack,skosukhin/spack,EmreAtes/spack,iulian787/spack,tmerrick1/spack,matthiasdiener/spack,skosukhin/spack,LLNL/spack,mfherbst/spack,LLNL/spack,matthiasdiener/spack,skosukhin/spack,tmerrick1/spack,krafczyk/spack,tmerrick1/spack,EmreAtes/spack,lgarren/spack,mfherbst/spack,iulian787/spack,krafczyk/spack,LLNL/spack,lgarren/spack,iulian787/spack,skosukhin/spack,krafczyk/spack,matthiasdiener/spack,EmreAtes/spack,LLNL/spack,lgarren/spack,matthiasdiener/spack,EmreAtes/spack,matthiasdiener/spack,LLNL/spack,mfherbst/spack,tmerrick1/spack