full cmake 6/N: generator

[loriab]

Currently atop #314 but has also been rebased to master so atop 2.8.1 . New stuff in 85e20ce .

• builds and runs the generator/compiler. A counterpart GHA has been added to test these stages for Mac & Linux.
• added a cmake file to prevent in-source builds. Requires setting CMAKE_BUILD_TYPE explicitly (or I can put in a default). Multiconfig generators seem unlikely with L2.
• testing enabled by usual cmake var BUILD_TESTING. Between master and the 2022/2023 CMake PRs, compiler tests and library tests changed places as being in top-level tests/ (see chart below). I was going to keep all the files in-place for now so that libtool and cmake can share. The main test.cc is in place and running through check-libint2compiler target.
• the main libtool generator test seems to be the test_eri/ that generates a dozen or so mini libraries and runs them through a tester. you didn't migrate this along with the other tests in ~2022, but it probably should be?
• windows. I carried the build-compiler/generator-on-windows cmake along and started to put it into GHA. This was mostly pointless b/c past work shows the export produced by Windows doesn't produce correct integrals. I stopped and discarded the effort b/c even the GHA "checkout" errored on the Pople star basis set files. Possibly a filtered checkout could get around this.

2023-PR                             CURRENT-LIBTOOL         CURRENT-CMAKE
-------                             ---------------         -------------
tests/core/                         src/bin/profile/        src/bin/profile/ (no actual test)
tests/core/test.cc                  src/bin/libint/test.cc  src/bin/profile/ (test set up from profile; test.cc borrowed from ../libint/)
tests/eri/                          src/bin/test_eri/       src/bin/test_eri/ (no actual test)
src/lib/libint/tests/eri/           tests/eri/
src/lib/libint/tests/unit/          tests/unit/
src/lib/libint/tests/hartree-fock/  tests/hartree-fock/
src/lib/libint/tests/fortran/       export/fortran/