added Slurm examples for CLAIX-2023

slurm/beeond_job.sh

slurm/gpu_job_1gpu.sh

slurm/gpu_job_2gpus-1proc.sh

slurm/gpu_job_2gpus-2procs.sh

slurm/gpu_job_4gpus-4procs.sh

slurm/gpu_job_8gpus-8procs.sh

slurm/hybrid_mpi_openmp_job.sh

slurm/mpi_job_1node.sh

slurm/mpi_job_2nodes.sh

slurm/mpi_job_basic.sh

slurm/openmp_multi-threading_job.sh