[EPIC]: Transition to spack. Deprecate thirdPartyLibs

[rrsettgast]

What is the requested feature? It is time to say farewell to our thirdPartyLibs repository, and the cmake build system for our TPL's. We have a viable spack configuration setup, so we should finish it up and proceed with the transition. Steps:

• [ ] Get spack config working for our target platforms on LC (@bmhan12),...
• [ ] and Pangea2, pangea3, pecan, etc (@TotoGaz)
• [ ] Develop TPL deployment strategy to replicate what is currently done. i.e. when the thirdPartyLibs are built, then are sent up to dockerhub for use with the main repo CI...and they are deployed to Total systems. I think this might require the spack config be placed in a submodule? Ideas?
• [ ] The documentation needs to be updated.

Libraries

• [ ] Mathpresso doesn't have a package, do we need it?
• [ ] VTK does have a package but it's huge, someone should strip it down.
• [x] The support for HYPRE+cuda appears to be there in Spack develop, but I haven't tried.

[untereiner]

@bmhan12 Wouldn't it be cleaner to have a separate repository (something like a "geos-installer") that contains all spack env or uberenv files and spack recipes, etc. ?