optional fortran compiler, adjustable cmake config installation

[loriab]

Description

User API & Changelog headlines

Dev notes & details

• It turns out one can build a psi4 with Fortran extensions (detected, not compiled) w/o a Fortran compiler by letting the CXX compiler handle the linking. This is very useful on Windows where we want a clang-cl C/CXX compiler, but the only cohesive Fortran-including stack is the ming (gcc/g++/gfortran) one. So this adds an option psi4_SKIP_ENABLE_Fortran to not enable Fortran when the code otherwise would. It doesn't check that the circumstances are suitable (that is, all detected, none to-be-compiled). Works great on Windows (that's how the conda pkg has dkh); haven't tried it on Linux.
• Increasingly, where the Config.cmake files get installed to is configurable, esp. as there's no one place cmake looks for linux/mac/win. So adding that option psi4_INSTALL_CMAKEDIR. You won't see a change unless you were customizing CMAKE_INSTALL_DATADIR.
• also fix a couple install locations that were obvious for windows install.
• stop testing the extra cli qcf tests for qcf master since those are run on mac, and it hangs.

Checklist

• Tests added for any new features
• All or relevant fraction of full tests run

Status

• Ready for review
• Ready for merge