Fix multiple gpu support

[joshkamm]

11/8/24: I'm currently meeting with Paul and we are looking into why this isn't working. Paul removed USE_ACC preprocessor statements to ensure that ACC pragma statements are immediately preceding loops.

Paul thinks if you try to compute the 3 center integrals on multiple GPUs it will fail. He modified compute_ints in hartree.cpp to only use 1 GPU for the 3 center integrals. Search for "CPMZ kludge"

We should finish SlaterGPU/#16 and then come back to this.